Add support for vSphere CSI plugin

[xmudrii]

What this PR does / why we need it:

This PR:

• Adds a new embedded addon used to deploy the vSphere CSI plugin
  • This addon is deployed automatically if .cloudProvider.csiConfig is provided and .cloudProvider.external is enabled
    • This is the same behavior as for OpenStack
• Adds a new API field .cloudProvider.csiConfig to be used with CSI plugins
  • vSphere has different configuration file formats for CCM and CSI, therefore dedicated fields for cloudConfig and csiConfig are required
    • The CCM and CSI configs are very similar. There are two key differences:
      • The CSI plugin requires providing cluster-id property. Providing this property in the CCM configuration causes the CCM to crash because the field doesn't exist
      • The CSI driver requires credentials to be provided as plain-text instead of referring to the Kubernetes Secret
• Updates the list of embedded addons
• Block provisioning 1.22 clusters or upgrading to 1.22 for vSphere
  • The reason behind this is that vSphere CCM and CSI don't support Kubernetes 1.22 yet

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Relevants to #1471

Does this PR introduce a user-facing change?:

* Add vSphere CSI addon
  * Deploying the CSI plugin/driver requires providing CSI config using a newly added .cloudProvider.csiConfig field
  * The CSI plugin/driver is deployed automatically if .cloudProvider.csiConfig is provided and .cloudProvider.external is enabled
* Block creating 1.22 clusters or upgrading to 1.22 for vSphere because CCM and CSI don't support Kubernetes 1.22 yet

/assign @kron4eg

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[kubermatic-bot]

LGTM label has been added.

Git tree hash: 3d4d1fe8551eae099fd25bdff3ff8f7fb8ae641f