This removes the `config` subcommand from the cli and the documentation
to keep the api surface small.
While this functionality was convenient it doesn't need to be surfaced
by the clan cli.
The remaining `config` python module should be ported to the `clan-app`
in a follow up pr. Because the functionality is currently only used by
the `clan-app`.
Ideally together with: #1830.
Also done:
- add @pytest.mark.with_core indicating that a test depends on clan-core and cannot be cached
- separate unit tests into two derivations, ones that can be cached and ones that cannot.
- fix frontend typescript code
