This decreases in smaller transaction which won't timeout

Related to T2160

Related to T2134
Related to D2409
Related to D2410

Related to T2134

The following commit adapts the return statements from both lister and their
associated tasks. This standardizes on what other modules (e.g. both dvcs and
package loaders) do.

This also adds tests to make sure that we properly send our version number to
upstreams.

And remove unnecessary fixture redefinition which causes indirection.

The scheduler module no longer initializes itself those task_type.

It's now defined in swh.scheduler

Otherwise, we are failing unicity constraint.

Related to T2070

Related bb5d405

This happens if swh.scheduler.celery_backend.config isn't imported
before the CLI runs.

Related to 56d7cff6

This also modifies the test dataset to filename with url decoded filename.
As this is what the latest pytest plugin requires.

That fixes the `swh lister run --lister debian` cli entrypoint.

By adding a `retries_left`

Instead of the old origin dict. That's what the debian loaders (old and new)
expect.