[release-1.6] ✨ Implement image promotion sync Makefile from core CAPI

[sbueringer]

What this PR does / why we need it:
Manual cherry-pick of #2101 and #2109

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Part of #2051

[k8s-ci-robot]

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

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-provider-vsphere-verify-main	aa619dd	link	true	/test pull-cluster-api-provider-vsphere-verify-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.

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[sbueringer]

/easycla

[randomvariable]

/retest
/approve
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: b450fe04545160650bd3e47f6b3c6150ac083ab3

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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[sbueringer]

Did a commit --amend & push force to get rid of the "main" job. lgtm should be preserved with our new test-infra config