Allow users to define config values which are read form environemnt
variables. Helpful for sensitive variables such as OAuth2 client IDs
or LDAP credentials.
Some OpenID Connect providers, notably Google, don't follow the spec
and allow refresh tokens to be requested with the "offline_access"
scope. Try to determine which we're talking to by checking the
supported_scopes listed by the provider discovery.
Since we don't have a good strategy which takes a username and password
add a mock connector which implementes PasswordConnector so we can
develop the frontend screens.
It's not clear that the best way to manage clients is through a
gRPC based command line tool. For example we may explore an admin
dashboard and enable bootstrapping through static clients.
For now use static clients while we hold off on a more concrete
proposal.
