Improve explanation in the README

[firefoxlover]

Problem

I think this software may be very important for Flatpak security to be adopted everywhere.

Proposal

Please improve the readme, as I currently cannot quickly grasp what it does, verify hashsums, crypto signatures, etc?

It would be great to make it more accessible

Prior Art (Optional)

No response

[danirabbit]

Ah yeah there's not much of an accurate description here. This is intended to use Flatpak's authenticators system to provide cross-platform payments for the AppCenter remote. So it's not super relevant for other remotes and is currently in kind of a prototype state