Rewrite manifest using common CDNs

Right now, the manifest uses many external resources who are mirrored in a second repository:
https://github.com/linuxhw/hw-probe

This is not really great, since it makes it very hard to update this Flatpak without some serious retooling. It also helps with security auditing.

Therefore, I would ask you to change your build-dependencies to packages that come directly from https://pypi.org and similar.