loaders, listers: Unify celery & sentry configuration

This makes the sentry setup really optional. This unifies in another commit the celery configuration like other deployments do (cookers, ...).

This allows to make those loaders run in minikube without crashing during the pod initialization step.

This also aligns the deposit charts.

Note: They are still crashing but after the pod is started (so celery starts). In the end, at some point, when we'll integrate real backends to serve them, they could actually run in minikube.