TYPO3's Mailer implementation does now dispatch
two new PSR-14 events.

The `BeforeMailerSentMessageEvent` can be
used to manipulate the message and the envelope
before being sent.

The `AfterMailerSentMessageEvent` can be used
to add further processing after the message has
been sent.

Resolves: #93689
Releases: main
Change-Id: I02ec5ad5b7a18f9f6f4f7146b676f7ce773d3b29
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74825

Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: André Buchmann <andy.schliesser@gmail.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Bartsch <bo@cedev.de>