Add/improve import for kubernetes and node pool resources

[optik-aper]

Description

• Adds node pool import state function
• Updates some state read on kubernetes resource to not trip re-creation when a cluster is imported
• Throw an error if a kubernetes cluster is imported and does not have the default node pool tag
• Document the imports for each

Checklist:

• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you linted your code locally prior to submission?
• Have you successfully ran tests with your changes locally?