In case a config was changed, we need to:
- Stop the ContentIndexer (bug 373430)
- Remove all scheduled indexing of files that should not be indexed
- Check for stale index entries. Those includes documents marked for indexing, that should be removed
(because of that we need to do it inside scheduleIndexing before content indexing)
- Finally, check for unindexed files (if new files were added)
(based on D15939: Perform checks for unindexed files and stale index entries on startup). Also note that IndexCleaner should clean all files, not just those inside includeFolders
BUG: 373430