[typescript-angular] drop support of angular below 6.0.0

Created by: macjohnny

Remove support for old angular versions below 6.0.0, allowing to clean up the code base.

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

cc @TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02)

bin/windows/typescript-angular-petstore-all.bat

-call .\bin\windows\typescript-angular-v2-with-npm.bat
-call .\bin\windows\typescript-angular-v2-interfaces.bat
-call .\bin\windows\typescript-angular-v2.bat
-call .\bin\windows\typescript-angular-v4-with-npm.bat
-call .\bin\windows\typescript-angular-v4.3-with-npm.bat
 call .\bin\windows\typescript-angular-v6-provided-in-root.bat
 call .\bin\windows\typescript-angular-v6-provided-in-root-with-npm.bat
 call .\bin\windows\typescript-angular-v6-not-provided-in-root.bat

bin/windows/typescript-angular-v2-interfaces.bat

-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -g typescript-angular -o samples\client\petstore\typescript-angular-v2\with-interfaces --additional-properties withInterfaces=true --additional-properties ngVersion=2
-
-java %JAVA_OPTS% -jar %executable% %ags%

bin/windows/typescript-angular-v2-with-npm.bat

-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -c bin\typescript-petstore-npm.json -g typescript-angular -o samples\client\petstore\typescript-angular-v2\npm --additional-properties ngVersion=2
-
-java %JAVA_OPTS% -jar %executable% %ags%

bin/windows/typescript-angular-v2.bat

-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -g typescript-angular -o samples\client\petstore\typescript-angular-v2\default --additional-properties ngVersion=2
-
-java %JAVA_OPTS% -jar %executable% %ags%

bin/windows/typescript-angular-v4-with-npm.bat

-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -c bin\typescript-petstore-npm.json -g typescript-angular -o samples\client\petstore\typescript-angular-v4\npm --additional-properties ngVersion=4
-
-java %JAVA_OPTS% -jar %executable% %ags%

bin/windows/typescript-angular-v4.3-with-npm.bat

-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -c bin\typescript-petstore-npm.json -g typescript-angular -o samples\client\petstore\typescript-angular-v4.3\npm --additional-properties ngVersion=4.3
-
-java %JAVA_OPTS% -jar %executable% %ags%

bin/typescript-angular-petstore-all.sh

 #!/bin/sh
 
-./bin/typescript-angular-v2-petstore.sh
-./bin/typescript-angular-v2-petstore-with-npm.sh
-./bin/typescript-angular-v2-petstore-interfaces.sh
-./bin/typescript-angular-v4-petstore-with-npm.sh
-./bin/typescript-angular-v4.3-petstore-with-npm.sh
 ./bin/typescript-angular-v6-petstore-not-provided-in-root.sh
 ./bin/typescript-angular-v6-petstore-not-provided-in-root-with-npm.sh
 ./bin/typescript-angular-v6-petstore-provided-in-root.sh

bin/typescript-angular-v2-petstore-interfaces.sh

-#!/bin/sh
-
-SCRIPT="$0"
-echo "# START SCRIPT: $SCRIPT"
-
-while [ -h "$SCRIPT" ] ; do
-  ls=`ls -ld "$SCRIPT"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '/.*' > /dev/null; then
-    SCRIPT="$link"
-  else
-    SCRIPT=`dirname "$SCRIPT"`/"$link"
-  fi
-done
-
-if [ ! -d "${APP_DIR}" ]; then
-  APP_DIR=`dirname "$SCRIPT"`/..
-  APP_DIR=`cd "${APP_DIR}"; pwd`
-fi
-
-executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
-
-if [ ! -f "$executable" ]
-then
-  mvn -B clean package
-fi
-
-# if you've executed sbt assembly previously it will use that instead.
-export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g typescript-angular -o samples/client/petstore/typescript-angular-v2/with-interfaces --additional-properties ngVersion=2,withInterfaces=true $@"
-
-java $JAVA_OPTS -jar $executable $ags

bin/typescript-angular-v2-petstore-with-npm.sh

-#!/bin/sh
-
-SCRIPT="$0"
-echo "# START SCRIPT: $SCRIPT"
-
-while [ -h "$SCRIPT" ] ; do
-  ls=`ls -ld "$SCRIPT"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '/.*' > /dev/null; then
-    SCRIPT="$link"
-  else
-    SCRIPT=`dirname "$SCRIPT"`/"$link"
-  fi
-done
-
-if [ ! -d "${APP_DIR}" ]; then
-  APP_DIR=`dirname "$SCRIPT"`/..
-  APP_DIR=`cd "${APP_DIR}"; pwd`
-fi
-
-executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
-
-if [ ! -f "$executable" ]
-then
-  mvn -B clean package
-fi
-
-# if you've executed sbt assembly previously it will use that instead.
-export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g typescript-angular -c bin/typescript-petstore-npm.json -o samples/client/petstore/typescript-angular-v2/npm --additional-properties ngVersion=2 $@"
-
-java $JAVA_OPTS -jar $executable $ags

bin/typescript-angular-v2-petstore.sh

-#!/bin/sh
-
-SCRIPT="$0"
-echo "# START SCRIPT: $SCRIPT"
-
-while [ -h "$SCRIPT" ] ; do
-  ls=`ls -ld "$SCRIPT"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '/.*' > /dev/null; then
-    SCRIPT="$link"
-  else
-    SCRIPT=`dirname "$SCRIPT"`/"$link"
-  fi
-done
-
-if [ ! -d "${APP_DIR}" ]; then
-  APP_DIR=`dirname "$SCRIPT"`/..
-  APP_DIR=`cd "${APP_DIR}"; pwd`
-fi
-
-executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
-
-if [ ! -f "$executable" ]
-then
-  mvn -B clean package
-fi
-
-# if you've executed sbt assembly previously it will use that instead.
-export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g typescript-angular -o samples/client/petstore/typescript-angular-v2/default --additional-properties ngVersion=2 $@"
-
-java $JAVA_OPTS -jar $executable $ags

bin/typescript-angular-v4-petstore-with-npm.sh

-#!/bin/sh
-
-SCRIPT="$0"
-echo "# START SCRIPT: $SCRIPT"
-
-while [ -h "$SCRIPT" ] ; do
-  ls=`ls -ld "$SCRIPT"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '/.*' > /dev/null; then
-    SCRIPT="$link"
-  else
-    SCRIPT=`dirname "$SCRIPT"`/"$link"
-  fi
-done
-
-if [ ! -d "${APP_DIR}" ]; then
-  APP_DIR=`dirname "$SCRIPT"`/..
-  APP_DIR=`cd "${APP_DIR}"; pwd`
-fi
-
-executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
-
-if [ ! -f "$executable" ]
-then
-  mvn -B clean package
-fi
-
-# if you've executed sbt assembly previously it will use that instead.
-export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g typescript-angular -c bin/typescript-petstore-npm.json -o samples/client/petstore/typescript-angular-v4/npm --additional-properties ngVersion=4 $@"
-
-java $JAVA_OPTS -jar $executable $ags

bin/typescript-angular-v4.3-petstore-with-npm.sh

-#!/bin/sh
-
-SCRIPT="$0"
-echo "# START SCRIPT: $SCRIPT"
-
-while [ -h "$SCRIPT" ] ; do
-  ls=`ls -ld "$SCRIPT"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '/.*' > /dev/null; then
-    SCRIPT="$link"
-  else
-    SCRIPT=`dirname "$SCRIPT"`/"$link"
-  fi
-done
-
-if [ ! -d "${APP_DIR}" ]; then
-  APP_DIR=`dirname "$SCRIPT"`/..
-  APP_DIR=`cd "${APP_DIR}"; pwd`
-fi
-
-executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
-
-if [ ! -f "$executable" ]
-then
-  mvn -B clean package
-fi
-
-# if you've executed sbt assembly previously it will use that instead.
-export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g typescript-angular -c bin/typescript-petstore-npm.json -o samples/client/petstore/typescript-angular-v4.3/npm --additional-properties ngVersion=4.3 $@"
-
-java $JAVA_OPTS -jar $executable $ags