Switch templates to use appctl instead of the launcher binary

The launcher binary is not part of the upstream rpm build (because
it's not properly namespaced), so it cannot be used in the desktop
file.
Update templates from gtk-js-app

1) Use systemd for bus activation
2) Use gapplication tool for legacy activation
3) Add rpm spec files
4) Move resource to ${name}.data.gresource
5) (JS only) Pack all sources into ${name}.src.gresource