Consider limited kubeconfig for internal components and consumers

[enxebre]

User Story

As a developer/user/operator I would like to CAPI core internal components to be granted only with the perms they need.

Detailed Description

Today CAPI generates a full admin config that is then consumed by the Machine Controller and by any component claiming a cluster accessor through the remote cache tacker, i.e r.Tracker.GetClient(ctx, util.ObjectKey(cluster)).

The Machine controller shouldn't need full admin client to operate successfully.
There might be other components needing narrowed set of permissions:

• Autoscaling.
• Azure AD for cluster authentication https://capz.sigs.k8s.io/topics/aad-integration.html (if you have the admin kubeconfig it kind of defeats the purpose).

This is to discuss alternatives for:
1 - Create limited kubeconfigs for consumption of our internal core components.
2 - Consider providing a way to express desired for capi outputting t-shirt size / limited kubeconfigs.

Anything else you would like to add:

[Miscellaneous information that will assist in solving the issue.]

/kind feature

[enxebre]

cc @CecileRobertMichon @voor

[fabriziopandini]

Somehow related to this #3661
TBD if we can dedup/merge

[vincepri]

/kind proposal
/milestone Next

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/lifecycle stale

[fabriziopandini]

/remove-lifecycle stale

[vincepri]

/lifecycle frozen
/help

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@vincepri:
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[fabriziopandini]

/triage accepted

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This issue has not been updated in over 1 year, and should be re-triaged.

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/remove-triage accepted

[fabriziopandini]

/priority important-longterm

[fabriziopandini]

This is still important to improve the security posture of CAPI itself
/triage accepted