Add support for AzureDisk CSI driver

[xmudrii]

What this PR does / why we need it:

• Add AzureDisk CSI driver addon
• Automatically deploy AzureDisk CSI driver addon if external cloud controller manager (.cloudProvider.external) is enabled
• Add default StorageClass for AzureDisk CSI driver to the default-storage-class embedded addon

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 #1571
Fixes #1566

Special notes for your reviewer:

This PR has been manually tested using the following manifest:

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-azuredisk
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: azuredisk-csi
---
kind: Pod
apiVersion: v1
metadata:
  name: nginx-azuredisk
spec:
  nodeSelector:
    "kubernetes.io/os": linux
  containers:
    - image: mcr.microsoft.com/oss/nginx/nginx:1.19.5
      name: nginx-azuredisk
      command:
        - "/bin/bash"
        - "-c"
        - set -euo pipefail; while true; do echo $(date) >> /mnt/azuredisk/outfile; sleep 1; done
      volumeMounts:
        - name: persistent-storage
          mountPath: "/mnt/azuredisk"
  volumes:
    - name: persistent-storage
      persistentVolumeClaim:
        claimName: pvc-azuredisk

Does this PR introduce a user-facing change?:

* Add AzureDisk CSI driver addon
* Automatically deploy AzureDisk CSI driver addon if external cloud controller manager (.cloudProvider.external) is enabled
* Add default StorageClass for AzureDisk CSI driver to the default-storage-class embedded addon

/assign @kron4eg

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: xmudrii

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• OWNERS [xmudrii]

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[kron4eg]

🎉

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 0927c34812013d80afea6e76088b762f15c9b6b5

[xmudrii]

/retest