feat(operator)!: Introduce v1alpha2 Role and RoleGroup - #1287

Proposed CRD shape

spec:
  role:
    roleGroup:
      replicas:
        # Use a fixed number of replicas
        fixed:
          count: 2

        # Or: Use a fully-managed (by us), auto-scaled number of replicas
        managed: {}

        # Or: Use a auto-scaled number of replicas managed by external/custom mechanisms
        custom: {}

Summary of changes

This PR includes a bunch of changes:

• The Role and RoleGroup types are now versioned via our versioned macro.
• It introduces two new versions: v1alpha1 and v1alpha2. v1alpha1 represents the shape of these types unchanged up until now. v1alpha2 introduces the changes which made versioning these types necessary at all.
• In v1alpha2 the replicas field was changed from a simple Option to a complex enum to support our planned auto-scaling mechanism.

This is a breaking change for primarily two reasons:

• The shape of Role and RoleGroup changed in v1alpha2.
• The location of the Role, RoleGroup, and supporting code (like function and helper types) changed. The code is now located at stackable_operator::crd::role.