Fixed Content Feeder to Detect Cycles in CMS Catalog Categories

Fixed a bug in the Content Feeder to not run into a StackOverflowError, if there is a cycle in children links of CMCategory content items.

(CMS-25907)

Additional Information on Blob Sharing Configuration Options

New blob sharing configuration options for Content Servers have been documented recently (sql.store.generate-blob-ids and sql.store.read-only-media-store-names). These are currently only to be used with integration of the Image Transformation Service and Blob Service and must not be used in projects otherwise. An additional note in the documentation makes this restriction clear now.

(CMS-25632)