ci: update to use freedesktop ci-templates, fedora 32, a better build script and to publish documentation
This is based on what I did for wireplumber yesterday: https://gitlab.freedesktop.org/pipewire/wireplumber/-/blob/master/.gitlab-ci.yml
... which is in turn based on weston: https://gitlab.freedesktop.org/wayland/weston/-/blob/master/.gitlab-ci.yml
CC @arun