[TASK] Fix broken references in LegacyClassesForIde

The LegacyClassesForIde.php contains some class definition
which extend non-existing or wrong classes.

Also fix some issues in ClassAliasMaps of ext:frontend

Resolves: #54059
Releases: 6.2
Change-Id: Id0918cfc3b187ea1110ad5e745a2b904ea50502c
Reviewed-on: https://review.typo3.org/25750
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn