Publish Helio to flathub as flatpak

[gozes]

I given that most of the audio-related plugins are pack as flatpak it would be grate to have Helio as well package as flatpak to make it easier to run it on any linux distro

[peterrudenko]

It is already published if I'm not missing anything, check out https://flathub.org/apps/fm.helio.Workstation