✨ Add dynamic completion support for context in kubeconfig and namespace

[superbrothers]

What this PR does / why we need it:

This PR adds dynamic completion support for context in kubeconfig and namespace.

• --kubeconfig-context flag
• clusterctl move --to-kubeconfig-context flag
• --namespace flag
• --target-namespace flag
• --from-config-map-namespace flag

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
ref/ #4089

[k8s-ci-robot]

Hi @superbrothers. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[sbueringer]

/ok-to-test

[superbrothers]

How can I modify this PR to pass pull-cluster-api-apidiff-main test? The CI result is correct because I have added a new method in this PR.

[sbueringer]

How can I modify this PR to pass pull-cluster-api-apidiff-main test? The CI result is correct because I have added a new method in this PR.

@superbrothers I think there's no reasonably easy way to do it. But apidiff is not required for merge and I think we don't have strong compatibility guarantees for clusterctl which would prevent your changes (but let's wait for Fabrizio's opinion on that).

[superbrothers]

@enxebre @JoelSpeed ping

[JoelSpeed]

Have had a read through, no additional feedback from me, though I'm not an expert in this area. Code looks clean, I think I understand what it's doing and how it should work, so LGTM.
/lgtm

[superbrothers]

/assign @CecileRobertMichon

[k8s-ci-robot]

@superbrothers: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Rerun command
pull-cluster-api-apidiff-main	d1c7c0e	link	/test pull-cluster-api-apidiff-main

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[sbueringer]

/lgtm

[vincepri]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vincepri

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