[testing] Migrate CI to GH Workflow

Initial work adds Ubuntu, CentOS and Fedora

* CentOS and Fedora as docker containers.
* Fedora for stagetwo depends on py3.14 enablement for avocado.
* CentOS foreman tests to be added later, docker container and foreman
  may not behave as well.
* Tests for systemd and/or journals have been skipped for docker
  containers for the time being.
* Debian will be added later.
* 26.04 enablement is same as Fedora, plus waiting for the runners to
  be available in GH

Related: #4288
Signed-off-by: Arif Ali <arif-ali@ubuntu.com>

Author: arif-ali