Motivation for this change

There are many companion apps to 'fldigi' missing from nixpkgs. http://www.w1hkj.com/

This app is not really "audio" but rather is a digital communication platform primarily used for ham radio. The companion apps are external to fldigi but integrate into fldigi in the preferences.

Side comment: nixpkgs really needs a "ham radio" section in the package tree (not unlike applications/science). There are a ton of ham radio apps. Debian even has a dedicated distro/flavor for hams. Some of the existing ham apps are in "misc" and some in "audio" right now on nixpkgs. Just for now I put these fldigi apps in "misc" along side WSJTX because they are definitely not 'audio' apps.

This is my first P/R to nixpkgs so please tell me all things I need to do to correctly get this finished. I see a big checklist below but all I've done is create the packages and use them on my nixos machine for a few days. They work on Nixos and aren't complicated packages. I imagine they'd work anywhere that fldigi works.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • [ X] NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.