[TASK] Mark GridContainer form elements as deprecated

The form element GridContainer is useless, buggy
and will be removed in v10.

Resolves: #84222
Releases: master
Change-Id: I559155a6fc9c994ba306729d3a2afad867d5dcaa
Reviewed-on: https://review.typo3.org/56351


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>