Create a warning for OpenSUSE and NixOS due to low package availability

Just because one specific app (Mullvad) isn’t packaged for OpenSUSE doesn’t mean there has to be warning.

As per Repology :

| Total packages | Up to date ---|---|--- Arch | 12k | 9.6k (86.9%) OpenSuse Tumblweed | 16k | 9.9k (75.1%) Fedora 44 | 23k | 15k (70.0%) nixpkgs stable 26.05 | 115k | 71k (85.0%) for comparison: Debian 12 | 34k | 9.6k (33.5%)

By this logic, Arch should get a warning for having the lowest number of packages* and Fedora a warning for being less up to date than the other recommended distros. Silly, right?

*which is a bit meaningless anyway because some distros split the same thing into many small packages and others don’t