[!!!][FEATURE] Check TCA changes in ext_tables.php

TCA changes within ext_tables.php can be moved to
Configuration/TCA since core 6.2. Still having them in
ext_tables.php is highly discouraged since version 7 and
now breaks with version 8.

The patch adds a feature to the Install Tool to find
loaded extensions that still manipulate TCA within
ext_tables.php files.

Additionally, the frontend is changed to no longer load
ext_tables.php files for normal requests and thus actively
ignores TCA changes from those files. This way a frontend
specific cache file is removed and the patch is a preparation
of a possible core cache warmup phase.

Change-Id: Ib639462ec92f4faf788fd20596aa4e7ce311701a
Resolves: #78384
Releases: master
Reviewed-on: https://review.typo3.org/50328


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>