[FEATURE] Allow multiple recipients in email finisher

Also deprecate the single recipients options
in favor of their list successors.

Resolves: #80420
Releases: master
Change-Id: I5bad6da8809bd362110025296564e3eff0df70a4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60544


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>