[DOCS] 8.0 Part 7/5 - Add TOC for 8.0 docs

In order to make navigating the docs possible, we added the TOCs

Resolves: #
Releases: master
Change-Id: I91e03693743e299a20d5a0f580e927c99143647f
Reviewed-on: https://review.typo3.org/47352


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>