This change is to help separate the fact the namespacing by a `NodeId` is a
Radicle specific concern. The identifier can, in theory, be any kind of path
component, as long it is valid in Git.
The motivation for the change is to help separate the idea of a device's
`NodeId` vs an agent being an author – for future agent repository work.
Adds the new `migrate` sub-command to migrate the COB database.
Checks for version when opening the COBs database and suggests the
command on out of date version.
Also adds the 2nd migration to the COBs cache, which updates the patch
JSON schema.