Add ariadne sentry integration

An ariadne integration for sentry was recently added in sentry-python repository.

It enables to get better insight of GraphQL errors by attaching full GraphQL query and its response to sentry events.

We should use it in swh-graphql once the next release of sentry-sdk (> 1.31.0) is out by adding a gunicorn_config.py file as in swh-web.

I tested it in docker by hacking a bit and the sentry reports look indeed much better.