[FEATURE] improve indexing reliability

* Better guess of the file title give the file name
* Prevent memory exhausting when indexing PDF

Change-Id: If264a087ca1205808ec0fb5aad264629cf466432
Releases: 1.1.0
Fixes: #52119
Reviewed-on: https://review.typo3.org/23893
Reviewed-by: Fabien Udriot
Tested-by: Fabien Udriot