[java][spring] added springdoc support for service metadata and security

Created by: bluenick2k17

• Added the auto-generated OpenAPI 3 support for service metadata and security, using springdoc.
  • Changes made to SpringCodegen to add the new documentation config file (SpringDocConfiguration.java) to the list of auto-generated files
  • Added new template file: springdocDocumentationProvider.mustache for the Spring generator which builds SpringDocConfiguration.java
  • This can be validated by generating a java spring API using the default documentation provider, and examining target/generated-sources/openapi/src/main/java/org/openapitools/configuration/SpringDocConfiguration.java in the resulting API.
  • Updated spring samples in this PR can also be checked to see some examples of the new springdoc configuration files.
• CodegenSecurityTest was updated to test the new addition of the SpringDoc configuration, and test was cleaned up to reduce duplication when adding the additional documentation provider test.
• Fixed a piece of documentation and the connected code in SpringCodegen which still used Springfox verbiage, even though the default documentation provider is springdoc.

Some notes on the implementation:

• Did not remove Springfox, since it's marked for removal in 7.0.0: https://github.com/OpenAPITools/openapi-generator/issues/11553
• Current pull request supports basic and API key fully with the security info. Does not yet support Oauth2 completely since it would require a bunch more work into the template. Would affect the ability to use auth on the swagger-ui with Oauth2
• CodegenSecurity doesn't support a description field yet for the auth method, so as of now that support remains the same

Closes https://github.com/OpenAPITools/openapi-generator/issues/12220

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