Media Files Handler

This module tries to find ways around #3027324: [PP-2] When Media entities are deleted, the associated files are not deleted. and #2821423: Dealing with unexpected file deletion due to incorrect file usage. On each update of a media item this module checks if all files of this media entity are still used in any translation or revision:

• Files still used by an older revision are moved into private storage, because the file should not be public accessible any more.
• If the file field of the media entity is translatable, the files of translations of the current revision should not be touched, if the translation is published.
• If the file is not used in any revision or translation, set the file to temporary or delete it.
• If an published media entity get unpublished, move all files to private storage.
• If a media entity gets published, move the files of the current revision to public storage, if this is the original field definition.

In active development and not feature complete.