Block vSphere on K8s 1.22

[mlavacca]

What this PR does / why we need it:
Since the necessity to block Kubernetes v1.22 on vSphere emerged under certain specific scenarios, this PR aims at implementing a generally available mechanism to block unwanted Kubernetes versions without the need to write custom code in the API server. The extra-files secret (where versions.yaml and updates.yaml reside) has been improved by introducing a new file: provider-incompatibilities.yaml, whose structure is the following:

providerIncompatibilities:
- condition: always
  operation: CREATE
  provider: vsphere
  version: 1.22.*
- condition: externalCloudProvider
  operation: UPDATE
  provider: vsphere
  version: 1.22.*

Below are the parameters' details:

• condition: the condition that the cluster must match to trigger the incompatibility (e.g., the cluster using the external CCM)
• operation: the operation to be applied in (creation of a new cluster or update of an existing one)
• provider: the provider to which to apply the block
• version: the Kubernetes version to block (wildcards are allowed)

The conditions can be improved in the future, every field about the cluster or the datacenter is allowed (it's just a matter of a couple of lines of code).
Adding and removing constraints is very simple by using this mechanism: when in the future we'll allow using 1.22 clusters on vSphere, it will be enough to delete the above rules from the defaults.go file, without dealing with ad-hoc conditions embedded in the core code.

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 #7578

Special notes for your reviewer:

Documentation:

Does this PR introduce a user-facing change?:

NONE

[xrstf]

/retest

[mlavacca]

/assign @xmudrii

[mlavacca]

/retest

[xrstf]

/hold

temporarily. I'm doing something on CI. Nothing to worry about.

[xrstf]

/hold cancel

[kubermatic-triage-bot]

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[kubermatic-bot]

@kubermatic-triage-bot:

In response to this:

/retest
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[mlavacca]

@xmudrii LGTM lost after rebase (there was a conflict). Could you lgtm again please?

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 6f04bee4e7d608be01470bdef17b84d7c8f64c84