Inject fantoir-datasource in Airflow image

Summary:
The fantoir_fetch and fantoir_import DAGs require fantoir-datasource.

This multi-stage build uses rDS77691169e3a7 nasqueron/datasources image
to install fantoir-datasource and make it available for the DAGs.

Ref T1812

Test Plan: Run a container with airflow nasqueron shell and launch fantoir-datasource

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1812

Differential Revision: https://devcentral.nasqueron.org/D3283