[BUGFIX] Misspelled class name FrontendUserAuthtenication

Fix class name, rename file, fix usage
FrontendUserAuth*ten*ication
FrontendUserAuth*ent*ication

Change-Id: Id851db64a50a5938496dd4411caaec0bf7ba85af
Fixes: #43464
Releases: 6.1, 6.0
Reviewed-on: https://review.typo3.org/17925
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn