[TASK] Doctrine: migrate ext:backend/Controller/LoginController

Resolves: #75749
Releases: master
Change-Id: I1de410ed558c80647a5288ecf3bef78bb4497ad0
Reviewed-on: https://review.typo3.org/47757


Reviewed-by: Christoph Kratz <ckr@rtp.ch>
Tested-by: Christoph Kratz <ckr@rtp.ch>
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>