Deploy metadata indexers in production

The metadata indexers never ran yet. It's time they do. Do it.

Indexers:

• origin head (#1326 (closed))
• revision (#1375 (closed))
• origin (#1376 (closed))

Impacts:

• package indexer repository when the scheduling migration is done T1227
• adapt swh-site with new needed services manifest
• add new tasks in scheduler

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Migrated from T1324 (view on Phabricator)