[TASK] Rename USER_INT related variables in TSFE

The cryptic variables $INTiS_config and internal names are improved
by using "nonCacheable" as naming (everywhere where possible,
not modifying public API methods).

Resolves: #89660
Releases: master
Change-Id: Ia03b1d612f1787f3d927a3724d20cb06caeddc38
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62309


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Daniel Gorges <daniel.gorges@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Johannes Schlier
Reviewed-by: Daniel Gorges <daniel.gorges@b13.com>
Reviewed-by: Benni Mack <benni@typo3.org>