libhelium Kotlin template

[lleyton]

As the title says. Will depend on #26 first.

[leinardi]

Hey, I guess you'd like to provide Flatpak support for your template, do you think we could join forces in trying to solve this issue?
https://gitlab.com/gtk-kn/gtk-kn/-/issues/54

[lleyton]

I'd love to, I'll take a look at the issue later today