Handing status/context in the upstream CLI

[wtrocki]

Approach 1

Special error types would be perhaps be needed which are scoped to the data plane CLI.

From data plane CLI, keep it simple with no reference to what command you should use:

var NoRegistrySelectedError = errors.New("no service registry selected")

return NoRegistrySelectedError

When interpreting the error, add additional info:

if rerr, ok := err.(*NoRegistrySelectedError); ok {
  return fmt.Errorf("%w: use 'rhoas service-registry use' to select a registry or pass the `--registry-id` flag")
}

That is a simplistic approach which does not scale very well, but perhaps some kind of abstraction would be helpful to match errors.

Originally posted by @craicoverflow in #859 (comment)

[craicoverflow]

@wtrocki I have set this as "important-longterm", please change it if this is inaccurate.

[wtrocki]

done quick investigation for splitting this context. I is not that trivial.
We have 2-3 goals mixed here:

1. Making it easy to contribute to rhoas CLI
2. Making RHOAS CLI SDK (aka charmil)
3. Enabling upstream CLI's to exist as separate entities.

Relativistically we can think of 1 and maybe doing some of 2. 3 seems to be doable only once we nail SDK part and have some success stories with integration. Upstream CLI will have many extra implications and it is too early to get that without having proper SDK in the rhoas repo