[TASK] Deprecate \TYPO3\CMS\Core\Utility\MailUtility::mail()

Change-Id: I8375c8a3880d2de2df06c81aa21f056a0d6289a7
Releases: 6.1
Resolves: #42321
Related: #47037
Reviewed-on: https://review.typo3.org/16138
Reviewed-by: Markus Klein
Reviewed-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Reviewed-by: Stefan Neufeind
Reviewed-by: Benjamin Mack
Tested-by: Benjamin Mack