Add additional usage ping metrics for object storage

Problem statement

We currently have two different object storage code paths, background and direct uploads. We would like to only maintain one code path, direct uploads, however background uploads have more usage.

We don't have much visibility into what backends are used, or often one of these is configured.

Proposal

Add two additional fields to the usage ping for object storage:

• Object storage backend
  • Text field
  • Reports back which object storage backend has been configured, like: s3, azure, gcs, openstack, etc.
• Object storage uploader
  • Enum
  • None, Direct, Background (None is that object storage has not been configured)