1:1 chats v0 and v1 backup support

[ryanfkeepers]

v0

• The service can backup all data in a given category.
• The backup process can reduce the data it selects for backup by using selectors (necessary for testing).
• The backup path is complete and stable.
  • RepoRef describes the location of the data according to the storage provider.
  • Path Locations describes the human representation of each item’s location, as opposed to the storage path (repoRef).
• Backup Details entries contains a representation for that service, and includes the minimum necessary metadata for the data category.

v1

Delta queries are not supported for chats.

• Incremental Support
  • Kopia-assist during backup processing.