GNOME uses this for backgrounds so let’s add GNOME team to maintainers
and adopt GNOME coding style aimed at cleaner git diffs:
- Format with `nixpkgs-fmt`
- Inherit `moduleDir` variable since it has the same name
- Avoid re-using `pname` for `src` in case it is overwritten
- Use conventional attribute ordering
- Have one dependency per line in inputs
- Move comments closer to what they describe
- Wrap long substitute line
- Quote bash values
