🌱 Standardize api import aliases

[tobiasgiese]

What this PR does / why we need it:

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

This PR standardizes our API import aliases. Further, it removes to skip lint our conversion.go files.
Adopted from kubernetes-sigs/cluster-api#5830
Follow-up of Slack discussion https://kubernetes.slack.com/archives/CFKJB65G9/p1639063415164300

Special notes for your reviewer:

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

TODOs:

• squashed commits
• if necessary:
  • includes documentation
  • adds unit tests

/hold

_{Tobias Giese tobias.giese@daimler.com, Daimler TSS GmbH, legal info/Impressum}

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[jichenjc]

/lgtm

[seanschneeweiss]

/lgtm
_{Sean Schneeweiss sean.schneeweiss@daimler.com, Daimler TSS GmbH, Provider Information}

[tobiasgiese]

I need also an approve, as this PR was created before I was added to the maintainers list 😿

/hold cancel

[jichenjc]

/approve

2 lgtm now ~

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jichenjc, tobiasgiese

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