Remove community.kubevirt from Ansible 6

[mariolenz]

Removal of broken collection community.kubevirt from Ansible 6 (ansible-community/community-topics#92).

cc @felixfontein

[felixfontein]

What's still needed is a changelog entry for 6.0.0a2, something like

removed_features:
  - The community.kubevirt collection has been removed from Ansible 6. It has not been working with the
    community.kubernetes collection included since Ansible 5.0.0, and unfortunately nobody managed to
    adjust the collection to work with kubernetes.core >= 2.0.0. If you need to use this collection, you need
    to manually install community.kubernetes < 2.0.0 together with community.kubevirt.

(For this, you need to add a new release section 6.0.0a2: to 6/changelog.yaml with changes: in it and the above inside that one.)

Something similar also needs to be part of the release announcement for 6.0.0 and its alphas/betas/rcs (CC @dmsimard).

[felixfontein]

@mariolenz thanks for implementing this!

[felixfontein]

Follow-up PR for community.kubernetes: #116