This patch removes all usages of `$GLOBALS['TYPO3_REQUEST']`
in ext:felogin classes, by passing the extbase request object
to methods requiring access to request parameters. As a result,
the class `ServerRequestHandler` has been removed, which
was a wrapper class for `$GLOBALS['TYPO3_REQUEST']`.

Besides the removal of `$GLOBALS['TYPO3_REQUEST']`, the
following cleanup and modernisation tasks have been made:

- Use constructor property promotion
- Use constructor dependency injection
- Marked `LoginController` as `@internal`
- Corrected some comments in tests and method doc headers
- Simplify mock creation in some tests

Resolves: #99777
Releases: main
Signed-off-by: Torben Hansen <derhansen@gmail.com>
Change-Id: I94034fdcc83fc78c34173b119d829279f8260de8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77652


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>