support cluster api v1alpha4

[wentao-zh]

What this PR does / why we need it:
This PR makes provider supports clulster-api v1alpha4

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

Specify your PR reviewers:

/cc @gyliu513 @jichenjc @xunpan

Special notes for your reviewer:

/area provider/ibmcloud

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Release note:

[k8s-ci-robot]

@wentao-zh: PR needs rebase.

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[k8s-ci-robot]

Hi @wentao-zh. 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.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: wentao-zh
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[mkumatag]

@wentao-zh ibmcloud branch is not maintained anymore, can you please submit changes to main branch?

[wentao-zh]

@mkumatag Then main branch is based on vpc implementaion. My PR is based on generic ibmcloud implementation. So we need to discuss about how can it be merged.