[TASK] Overhaul record localization of Page module

This patch overhauls the record localization in the page module. The
"Translate" button opens now a modal window in which a user can choose
between translating and copying records into another language. This
replaces the split button introduced with 7.4.

Also, this patch removes the ``copyRecordFromLanguage`` method from
DataHandler again which was initially written for this purpose.

Resolves: #71224
Resolves: #70781
Releases: master
Change-Id: I3d61cbdfd6a1ccb7a5c93883634596ef62cc08f6
Reviewed-on: https://review.typo3.org/44460


Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Tested-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>