Add loader workers services
Also
- task_queues configuration is not needed any more
- Fix loader config file name
We should really consider being more consistant here:
- loaders: ~/.config/swh/loader/.yml
- listers: ~/.config/swh/lister-.yml
Require swh-scheduler!32 (closed), swh-scheduler!33 (closed) and swh-lister!47 (closed) to work properly.
Migrated from D902 (view on Phabricator)