[TASK] Add option to make domainobjects categorizable

Default-name for category-field is "categories".

Description how categorization is enabled:
http://wiki.typo3.org/TYPO3_6.0#Category

Change-Id: I046dcb805987ce5435a624399e1d966a5efc763a
Resolves: #56968
Reviewed-on: https://review.typo3.org/28451
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind