Publish Uno Calculator to Flathub

[Lenni-builder]

Problem Statement

Currently, Uno calculator is only available through a Snap package for Linux, which many people don't want to use.

Evidence or User Insights

I think many people prefer Flatpaks over Snaps, but I don't have any real evidence.

Proposal

Uno Calculator should also be published to Flathub, not only the Snap Store.

Goals

People who only have Flatpak installed on their system should be able to also use Uno Calculator, not only Ubuntu/Snap users.