[TASK] Move LoginProvider logic into a separate class

The LoginProvider functionality, which was baked into the LoginController
is now moved into a separate Resolver class, cleaning up the Controller
class and having a dedicated, single responsibility as a separate PHP class.

In addition, the Request/Response (PSR-7) functionality is now
used, instead of relying on $_COOKIE.

Resolves: #93947
Releases: master
Change-Id: Ic94361216566ec046160053e2a93c7d6be69584a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68772


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>