Adding variable control of kernel update

[cdunbar13]

It might not always be the best to update the kernel - especially with images that are built with specific kernel tied drivers in mind. This provides a mechanism to circumvent at least updating the kernel and release version.

[tpdownes]

Please follow the same pattern as Debian. e.g. in playbook.yml there should be a block that (non-optionally) freezes the kernel during build

  - name: Freeze kernel before running playbook
    when: ansible_os_family == "Debian"
    ansible.builtin.dpkg_selections:
      name: "{{ kernel_package }}"
      selection: hold

and then the final step should unfreeze it depending upon the setting of allow_kernel_upgrades.

  post_tasks:
  - name: Re-enable kernel upgrades by apt-get upgrade
    when:
    - ansible_os_family == "Debian"
    - allow_kernel_upgrades
    ansible.builtin.dpkg_selections:
      name: "{{ kernel_package }}"
      selection: install

The dnf exclude or dnf-versionlock plugins seem appropriate mechanisms.