Add support for openshift on AWS

[jtharm]

cluster name can be parsed out of current context for aws rosa or aws eks. The format is as follows:

rosa:

[terminal]$ kubectl config current-context
default/api-abc-def-j8jd-di-openshiftapps-com:6443/[email protected]

eks:

[terminal]$ kubectl config current-context
arn:aws:eks:us-east-1:01234567:cluster/cluster-name

The PR satisfies both outputs above with:

rosa: api-abc-def-j8jd-di-openshiftapps-com eks: cluster-name

[nathan-b]

I'm concerned that this change removes support for systems which are not openshift but also not aws, such as gcp. This would be a behavior change on those systems, right? Is that intended?

[jtharm]

If it's gcp and not openshift then it will be set via L223. This is identical to the flow of L237. Correct me if I'm wrong here.

[nathan-b]

Yes, it will work, but it will also print a weird error message which is not desirable[1]. If this is the intended flow, we should stop treating L229 - 234 as an error condition

[1] Weird error message from the user perspective, because they are trying to install in GCP and they're getting error references to IBM cloud

[nathan-b]

Closing due to lack of response. Please feel free to open a new PR and try again.