[!!!][TASK] Remove deprecated functionality in EXT:form

Any code/options related to EXT:form that has been deprecated
in v8 is now removed.

Resolves: #80710
Releases: master
Change-Id: Ieb41e86a80d5b76cc639110db82b21bf3b4d993f
Reviewed-on: https://review.typo3.org/52508


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Thomas Hohn <thomas@hohn.dk>
Reviewed-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Tested-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>