[TASK] Add missing breaking changes documentation

[TASK] Add missing breaking changes documentation

This patch adds missing documentation for the breaking changes
introduced in https://review.typo3.org/42644.

It also adds an early return for the FileListIsStartModuleUpdate
to prevent unnecessary database operations.

Releases: master
Resolves: #69237
Change-Id: Iaa113741919013b8a0a9513c1dcca2e5db094b04
Reviewed-on: http://review.typo3.org/42814
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>