Validate kubeconfig during provider configuration.

[swade1987]

Description

Validate kubernetes connectivity during provider configuration to reduce errors later on.

Motivation and Context

Fixes #656

How has this been tested?

• Have you added an acceptance test for the functionality being added?
• Have you run the acceptance tests on this branch?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Documentation

• I have updated the documentation (if required) with make docs

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s

Community Note

• Please vote on this issue by adding a 👍 reaction to the original issue to help the community and maintainers prioritise this request
• If you are interested in working on this issue or have submitted a pull request, please leave a comment

[networkhermit]

I notice that the validate logic triggers a ServiceAccountList request in default namespace. I don't know, but is it possible for it to get reported and marked by some audit framework? If that's the case, ServiceList or else would be more harmless candidate. (Correct me if it's just me being over cautious.)

[stefanprodan]

LGTM

Thanks @swade1987