[FEATURE] Extend collection handling by repository

The table sys_collection allows to group several objects and
persist them in one collection object. The data access shall
happen by a repository, which is integrated with this change
set.

Change-Id: Ib3401f2e3bd4c267f92aef59dbc36756b54cce0a
Resolves: #33755
Releases: 4.7
Reviewed-on: http://review.typo3.org/8913
Reviewed-by: Georg Ringer
Reviewed-by: Stefan Neufeind
Reviewed-by: Oliver Hader
Tested-by: Oliver Hader