[TASK] Remove possibility to use ext:rsaauth

Usage of FriendsOfTYPO3/rsaauth is pretty low and there
is no reason to support the extension any more in TYPO3 11.

This patch removes all ext:rsaauth related code.

Resolves: #94279
Releases: master
Change-Id: I8e318bcc3c04fcc66a033507d0dddb931529c17d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69397


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>