Fixed the errors in ignore generation process; added the abilities to select the version of libraries for Java, to hide sections in pom.xml

Created by: Nikolai-SE

Fixed next errors in ignore generation process with .openapi-generator-ignore:

1. All directories were generated in DefaultGenerator.generateSupportingFiles()
2. Empty directories weren't generated in DefaultGenerator.processTemplateToFile()

How these were fixed:

1. In method generateSupportingFiles() have deleted few code, that creates all directories.
2. Method processTemplateToFile() have become creating longest non-ignored path to file ( even the file ).

Useful additions for Java:

In order for the generated code to use the necessary versions of the libraries, it will be convenient to set them during the generation configuration. For example, by specifying the field '-version' (additionalProperties). To do this, the template files pom.mustache in java/libraries have been edited.

To hide some sections from the file pom.xml it will be convenient to set the configuration flags (additionalProperties): generate-licenses, generate-developers, generate-parent those are true default. To do this, the template files pom.mustache in java/libraries and code in AbstractJavaCodegen have been also edited.