The file cache was caching the `Unauthorized` errors if a user without
the right perms opened the file first. So all future opens would fail.
Now the cache always opens with a subject that can read files. And authz
is checked on the Acquire per user.
* chore: merge authorization contexts
Instead of 2 auth contexts from apikey and dbauthz, merge them to
just use dbauthz. It is annoying to have two.
* fixup authorization reference
* chore: add /v2 to import module path
go mod requires semantic versioning with versions greater than 1.x
This was a mechanical update by running:
```
go install github.com/marwan-at-work/mod/cmd/mod@latest
mod upgrade
```
Migrate generated files to import /v2
* Fix gen
* chore: Implement standard rbac.Subject to be reused everywhere
An rbac subject is created in multiple spots because of the way we
expand roles, scopes, etc. This difference in use creates a list
of arguments which is unwieldy.
Use of the expander interface lets us conform to a single subject
in every case
