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.
0a58adce18