Add ClusterFeatureCCMClusterName feature for OpenStack clusters

[xmudrii]

What this PR does / why we need it:

This PR introduces a cluster feature called ccmClusterName, which is used to apply the --cluster-name flag on the external CCMs. Currently, this flag is only applied on the OpenStack CCM. In the future, it will be applied for the other cloud providers that support the external CCM as well.

The --cluster-name flag is often used for naming cloud resources, such as Load Balancers. If it's not provided, the CCM would default it to kubernetes.

Not providing the cluster-name flag can cause conflicts as described in issue #7229.

It's not possible to easily change this flag for the existing user clusters, as it can cause the external CCM to lose track of the existing cloud resources. Therefore, we're introducing a feature flag with the following behavior:

• if it's enabled, add the --cluster-name flag on the external CCM deployment
• enable the flag by default for newly created clusters
• allow users to explicitly enable this flag for the existing clusters
  • in this case, it's up to the user to clean up any leftover resources
  • in the future, we might implement a migration mechanism that would automatically clean up leftover resources

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 #7332

Does this PR introduce a user-facing change?:

Add ClusterFeatureCCMClusterName feature for OpenStack clusters. This feature adds the --cluster-name flag to the OpenStack external CCM deployment. The feature gate is enabled by default for newly created clusters. Enabling this feature gate for existing clusters can cause the external CCM to lose the track of the existing cloud resources, so it's up to the users to clean up any leftover resources.

/assign @kron4eg

[kron4eg]

/approve

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 4c236699306ba6af379ab7669bc250d334b7ad05

[kron4eg]

@xmudrii looks like we also need someone from sig-api

[kron4eg]

/lgtm

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 90b84c93bbf9a4414457c6c54d1c5816e5308e40

[maciaszczykm]

/approve

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kron4eg, maciaszczykm, xmudrii

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• pkg/crd/OWNERS [kron4eg,xmudrii]
• pkg/handler/OWNERS [maciaszczykm]
• pkg/resources/OWNERS [kron4eg,xmudrii]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[xmudrii]

/cherry-pick release/v2.17

[xmudrii]

/cherry-pick release/v2.16

[kubermatic-bot]

@xmudrii: new pull request created: #7335

In response to this:

/cherry-pick release/v2.17

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[kubermatic-bot]

@xmudrii: new pull request created: #7336

In response to this:

/cherry-pick release/v2.16

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.