[DOCS] Remove References to "Inside TYPO3"

The reference "Inside TYPO3" is not available anymore since TYPO3 8.7.

The sentences are quite useless anyway.

Releases: main, 11.5, 10.4
Resolves: #97913
Change-Id: I2d496726db8b22de667d230a99f7d17341fd309d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75157


Tested-by: core-ci <typo3@b13.com>
Tested-by: Sybille Peters <sypets@gmx.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Sybille Peters <sypets@gmx.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75182