Summary: This avoids bugs/vulnerability with filenames containing a quote.

Reviewers: ardumont, moranegg, #reviewers

Reviewed By: ardumont, #reviewers

Differential Revision: https://forge.softwareheritage.org/D474

update current stats accordingly

[1] https://forge.softwareheritage.org/diffusion/SPRE/

Related T1069

Related T1071

+ add docstring

Related T682

Related T682
Related P221

Related T329

Use case: indexers.  To send new tasks for scheduling to the
orchestrator queue (input queue), we need to check the mimetype and
license indexers queues (not only the mimetype one).

to streamline running experiments with different parameters

also, updated Rabin fingerprint parameters for better compression rates

down to 25m for linux.git, from 1h for the single process version, from 14h for
the sqlite3 version

instead of sqlite3

even if we're not using COPY, it is *much* faster