Allow installing flatpak packages via system/packages or by directly depending on `flatpak/origin/com.application.Application`
Allow installing flatpak packages via system/packages strategy (similar as apt) or by directly depending on flatpak/<origin>/<com.application.Application>
as required module (pseudo-module as with apt/<package_name>
).
Tested on Ubuntu 18 and Ubuntu 22
Edited by Christian Dreher