Use Tag.metadata.uid as part of the snapshot URI

[juli4n]

Snapshots in object storage can be owned by either Actor or Tag resources. Who owns the resource dictates the base path under which they are stored.

• Actor: <base-location>/atespaces/<actor-atespace>/actors/<actor-uid>/snapshots/<snapshot-name>
• Tag: <base-location>/atespaces/<tag-atespace>/tags/<tag-name>

(both snapshot-name and tag-name are random UUID generated at snapshot creation time)

I think we should change the Tag case to be:

<base-location>/atespaces/<tag-atespace>/tags/<tag-uid>

This has a much nicer property, which for both resources that can own snapshots, you can find all the blobs they ever referenced under a given path.

I think using deterministic naming like this will also allow us to remove the Tag.status.in_progress_snapshot_uri field.

Luiz Oliveira (@laoj2)