[TASK] Optimize wording for reset backend password functionality

This change updates the email texts and subject lines for HTML and plain
text mails, as well as some labels in the backend.

Resolves: #90670
Releases: master
Change-Id: I1ac121097d784bcdf365f1e31c2ce37f53c73617
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63771


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>