PROPOSAL: change the use command structure

[richardcase]

Describe the solution you'd like:
Currently when you use you are required to specify the cluster provider as a positional argument and then the IdP protocol as a flag:

kconnect use eks --idp-protocol saml [other flags]

Would it make more sense to also specify the identity plugin via a position argument so you end up with:

kconnect use eks saml [flags]

What does everyone think? Would this feel more natural?

/cc @rajarajanpsj @seankelly001 @saada

[richardcase]

This would mean that there would be a tree of commands as a result, use->cluster provider->identity provider.

We'd also want to functionality that maps cluster providers to allowed identity providers.

[richardcase]

If we went with this approach you wouldn't be able to set the idp-protocol in config.yaml.

[richardcase]

Without doing this we need to have the forked version of Cobra where we can dynamically inject flags.

[richardcase]

If no --idp-protocol flag is supplied (and there is not value in the config file or env var) then we default to the first identity provider supported.

So i think perhaps we stay with what we have?