[FEATURE] Release the application with Flatpak on Flathub

Problem

The Linux package provided by OpenCut is now in deb, which is a Ubuntu/Debian ecosystem-specific format. It is a good thing that you provide a Linux package. It would be even better if a package format is provided for Linux regardless of distribution.

Solution

Flatpak is a cross-distribution, optionally sandboxed format for distributing Linux desktop application. It would be a more ideal format for Linux distribution. And Flathub is the main application for Flatpak package distribution.

It is a bit of work to modify pipeline to distribute as Flatpak package. But it would then allow other popular distributions (e.g. RHEL / Fedora, Arch Linux) to take advantage of this application.

Alternative

Alternatively, there is also snap, which is proposed and maintained by Canonical (the company behind Ubuntu). This is, in my mind, a less favourable format because the format requires install and running an additional background application (i.e. daemon) even if no snap application is running. Flatpak is, instead, only requires a set of application tool.

Anything else?

I am running my laptop on a Fedora environment. And there is no easy way to install OpenCut.

The issue mentions the existing deb package and release pipeline but names no files or tests. Start by locating the Linux packaging workflow and reviewing Flatpak and Flathub requirements; done means OpenCut can be built and published on Flathub for supported Linux distributions.