Geo: Spike Self-Service Framework with Package Files

Goal

• Create a new PackageFile
• See that the secondary attempted to request the PackageFile
• See the PackageFileRegistry exists but failed

This cuts across the first implementation issues of &2346 (closed):

• #118743 (closed)
• #118745 (closed)
• #118749 (closed)
• #118747 (closed)

Not promised

• If a PackageFile is deleted, Geo may not send an event yet
• Existing PackageFiles are not synced
• Documentation
• All necessary tests
• Downloading a PackageFile may not work yet (Uploading to be implemented in another iteration)

Promised

• Feature flagged with geo_self_service_framework
• General architecture and naming
• It is clear where to add a Delete event
• It is clear where to add a new Blob Type so that it would also be synced upon creation