Drop labels dedicated to cloud provider

[danpawlik]

When IBM private cloud would be removed, there is no need to keep
nodesets that would force spawning CI jobs on specific cloud
provider.

After merging: #3851

Depends-On: openstack-k8s-operators/watcher-operator#363

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign fultonj for approval. For more information see the Code Review Process.

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

Details

Needs approval from an approver in each of these files:

• OWNERS

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

[softwarefactory-project-zuul]

Zuul encountered a syntax error while parsing its
configuration in the repo openstack-k8s-operators/watcher-operator on branch main. The
problem was:

The nodeset "centos-9-medium-2x-centos-9-crc-cloud-ocp-4-18-1-3xl-
vexxhost" was not found.

The problem appears in the the "watcher-operator-base" job stanza:

job:
name: watcher-operator-base
nodeset: centos-9-medium-2x-centos-9-crc-cloud-ocp-4-18-1-3xl-vexxhost
parent: podified-multinode-edpm-deployment-crc-2comp
description: |
A multinode EDPM Zuul job which has one ansible controller, one
extracted crc and two computes. It will be used for testing watcher-operator.
Configures Nova and Cinder to send notifications over a dedicated rabbitmq instance.
vars:
...

in "openstack-k8s-operators/watcher-operator/.zuul.yaml@main", line 15