ci: use podman gitlab-runner for multiarch builds

The build runs in two stages:
1. Cross compilation for target architecture on native arch image
2. Installation into target architecture image

Currently it requires a third stage to workaround an issue in podman/buildah:
https://github.com/containers/buildah/issues/4742

Configuring a gitlab-runner with podman:
1. Follow this documentation:
   https://docs.gitlab.com/runner/executors/docker.html#use-podman-to-run-docker-commands
2. Install the `crun` and `qemu-user-static` packages