Refactor Gitlab::KubeClient

What does this MR do?

Refactors Gitlab::KubeClient to be slightly more flexible :

• Removes need to pass in array of api_groups
• Allows re-use of object for different api_version
• Handle special case of apis/extensions, it is only v1beta1 (no v1 !)

What are the relevant issue numbers?

Resolves https://gitlab.com/gitlab-org/gitlab-ce/issues/52131

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides