[FEATURE] Clear indexed_search documents when content is changed

A new feature flag enables indexed_search to remove the documents from
the index if the page or content is changed in the backend.

Resolves: #94577
Releases: master
Change-Id: I871978d15366c8d7ac560c82a29702678701db2c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69914


Tested-by: core-ci <typo3@b13.com>
Tested-by: kharaf <k.haraf@macopedia.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: kharaf <k.haraf@macopedia.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>