Cleanup deprecated configuration code in swh modules

Once every swh modules have been deployed, we should cleanup the tasks submodule's collaborator (lister/loader/indexer)'s no longer useful configuration.

Once again, one step closer to #1410, #826 (closed).

Also cleanup the remaining dangling debian/ tree arborescence in every module's master branch (debian packaging in swh modules starts in debian/unstable-swh branch now). Most if not all of the debian packaging should have been fixed once swh/infra/puppet/puppet-swh-site#1525 (closed) is done.

Then package and redeploy.

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Migrated from T1532 (view on Phabricator)