Reduce parallelism when fetching licensing data
With 30 concurrent threads we were ovehelming both our client-side HTTP connection pool and the GitLab server itself.
In the best case, we only got many warnings on the client side like:
INFO:root:Fetching component and license_report for 5745 projects
WARNING:urllib3.connectionpool:Connection pool is full, discarding connection: gitlab-apertispro.boschdevcloud.com
In other cases we got GitLab failing with many exceptions:
gitlab.exceptions.GitlabHttpError: 500
Some of those errors mapped to server side logs indicating exhaustion of the database connection slots:
connection to server at "10.0.69.74", port 5432 failed: FATAL: remaining connection slots are reserved for non-replication superuser connections