Add support for indexing intrinsic metadata from releases

The OriginMetadataIndexer expects the head of origins to be revisions, and ignore them when they are not.

This means we stopped indexing metadata from package-manager origins since #3638 (closed) was resolved.

Migrated from T4297 (view on Phabricator)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information