[FOLLOWUP][FEATURE] Add MetaTag API

Bring back the meta generator which got lost in the original patch

Resolves: #81464
Releases: master
Change-Id: I5c68e35bdab953c8ff3df3afd85099439ed42787
Reviewed-on: https://review.typo3.org/54554


Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>