[TASK] Deprecate TypoScriptFrontendController->getUniqueId

The unused method TypoScriptFrontendController->getUniqueId() is marked
as deprecated, as this method conceptually should go into a custom
service with a singleton pattern or a runtime cache, but not within
TypoScriptFrontendController.

Resolves: #85555
Releases: master
Change-Id: Ib3af4b32e3c03d90b832ee725dcf9846af92f9ba
Reviewed-on: https://review.typo3.org/57597


Reviewed-by: Josef Glatz <josef.glatz@typo3.org>
Tested-by: Josef Glatz <josef.glatz@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Tested-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>