[TASK] Migrate leftover userfunc for tt_content to hook class

One method still initialized on every uncached call
is user_sortPluginList() which is used in TCA tt_content
to sort all plugins by name (trivial, right?).

The patch moves the code in the right direction.

Releases: master
Resolves: #63006
Change-Id: I9be865ee3429e033a924b00d0e1b98ad4159c15e
Reviewed-on: http://review.typo3.org/34244
Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Reviewed-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Tested-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>