[TASK] Separate configuration into hooks for Indexer

This is a pre-patch to separate crawler-specific implementation from
the actual indexing configuration.

This first patch unifies the configuration creation for the indexer,
and places the configuration in each respective logic (see TSFE hook),
where as the Indexer does not know about TSFE or "called from Backend"
anymore, making the indexer just doing its work.

The next iteration will then separate all indexing logic into smaller
chunks again.

Resolves: #90920
Releases: master
Change-Id: I631ddd0839ee8f03d0a6c3c86d302b935e599a5e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64039


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>