staging: Deploy package loader v1.0, deposit server v0.16, lister v2.3

This changes the package loaders so they now create synthetic releases instead of synthetic revisions (check parent task for more details). This needs a coordinated deployment.

Plan:

• stop deposit loader
• upgrade deposit server
• upgrade packages loader
• restart lister service
• restart package loader services (ongoing)
• make sure it works (deposit loader is)
• check existing snapshots (with revisions as branches) are upgraded (to releases as branches)

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Migrated from T3722 (view on Phabricator)