Exclude FreeMarkerAutoConfiguration

FreeMarkerAutoConfiguration was excluded from studio server app configuration.

(CMS-17066)

Added documentation about adding new entity controlls to studio server

We added a new chapter to the studio-developer-manual about adding new entity controllers to the studio server. For this the interface com.coremedia.rest.controller.EntityController (previously named com.coremedia.rest.linking.EntityResource ) is now part of the Public API.

(CMS-14090)