Salt script broken

[palainp]

As initramfs is no longer needed (see #70) we will be able to release only the unikernel file. With that in mind, the salt script can be simplified (no more tar involved) and, in the process, we can try to check the hashsum against something other than the one in the build script (maybe the best option would be to ship a hashsum file along the unikernel file?).

This will allow PRs to be merged (like #199) without needing for an immediate release matching the hashsum (and that explains this issue's title :) ).

[palainp]

While preparing the next release, I wonder if a possible solution would be to have:

• a qubes-firewall.sha256 file containing the hashsum of the current head (the one used in GH actions)
• a qubes-firewall-release.sha256 file containing the hashsum of the latest release (the one used in the salt script)
• releases files will contain vmlinuz and qubes-firewall-release.sha256

Does anyone have a idea about that?

[palainp]

Done (or will be done) in #205