azure: fix chart bugs after AKS vmType deprecation

[jackfrancis]

What type of PR is this?

/kind bug

What this PR does / why we need it:

This PR fixes some chart errata introduced in #6186 (mea culpa). Specifically:

• PR Azure: Remove AKS vmType #6186 removed the "AKS" vmType configuration, and so we don't to default the azureVMType chart value to be "AKS"
• PR Azure: Remove AKS vmType #6186 removed the Azure provider "clusterName" configuration, so we don't want a reference to that as a required value in the chart deployment spec
• PR Azure: Remove AKS vmType #6186 removed the Azure provider "nodeResourceGroup" configuration, so we don't want a reference to that as a required value in the chart deployment spec

Here is a representative example in PR #6186 of the removals mentioned above:

• https://github.com/kubernetes/autoscaler/pull/6186/files#diff-e350455eeabc5662e1fc8162e570b2f45f95699270a30ce51443ba61afa49da6

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[mwielgus]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis, mwielgus

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• charts/OWNERS [mwielgus]

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