swh.scheduler.cli: Add `swh scheduler task-type register` cli
This allows registering of workers' task types within the scheduler backend.
Those are declared in their respective setup.py
's entrypoint
under the section [swh.workers]
.
(This is moved from swh.lister to swh.scheduler).
Test Plan
tox
Migrated from D2291 (view on Phabricator)