feat: MTV migrate role

[sabre1041]

Description

Added mtv_migrate role that enables triggering a migration from an existing plan

Type of Change

• feat: A new feature
• fix: A bug fix
• docs: Documentation changes
• style: Formatting, missing semi colons, etc; no code change
• refactor: Refactoring production code
• test: Adding missing tests, refactoring tests; no production code change
• chore: Updating configs, etc; no production code change

[tech2734]

Good stuff — the custom module with unit tests and the recursive polling pattern are solid. A few things I noticed:

1. meta/main.yml missing role_name: Should add role_name: mtv_migrate to galaxy_info for consistency with the other roles.

2. Playbook host filtering: vmf_migrate.yml targets migration_clusters group but doesn't have a guard to only execute on the relevant host. Might need a when condition or similar pattern to prevent running on all hosts in the group.

3. Missing OCP connection params on Create Migration task: The redhat.openshift.k8s call in main.yml doesn't pass host, api_key, validate_certs, or ca_cert — but the polling tasks in _poll_migration_status.yml do. Probably works via K8S_AUTH_* env vars in AAP, but it's inconsistent.

4. README boilerplate: The static section still has the generic Ansible Galaxy scaffolding ("pre-requisites that may not be covered", example string_arg1 argument spec, etc.). The docsible section below is fine — just the static part could use a cleanup pass.

5. _mtv_migrate_mtv_cutover referenced but not set: In migration.yml.j2, the template checks _mtv_migrate_mtv_cutover but I don't see a set_fact that populates it. mtv_migrate_warm_cutover_time is the user-facing default — looks like either a missing fact or a variable name mismatch.