firefoxPackages: add icecat, update tor-browser, misc cleanups

[oxij]

git log

• firefoxPackages.icecat: init at 60.3.0, 52.6.0

  It works, but this state is far from ideal: GNU guys update generated source
  tarballs very infrequently. Ideally, src needs to be generated by running
  makeicecat over firefox src. Will do later.

• firefoxPackages.tor-browser: 8.0.3 -> 8.0.4

• firefoxPackages.tor-browser: 8.0.4 -> 8.0.5

• firefoxPackages: add a comments explaining the purpose of older versions

• firefoxPackages.tor-browser: fix meta

• firefoxPackages: move nixpkgsPatches into common.nix

Environment

• Host OS: Linux 4.9, SLNOS 19.03
• Nix: nix-env (Nix) 2.1.3
• Multi-user: yes
• Sandbox: yes
• NIXPKGS_CONFIG:

{
  checkMeta = true;
  doCheckByDefault = true;
}

nix-env -qaP

• On x86_64-linux:
  New (2):

  • firefoxPackages.icecat
  • icecat
    Updated (2):
  • firefoxPackages.tor-browser
  • tor-browser-bundle

• On aarch64-linux:
  New (2):

  • firefoxPackages.icecat
  • icecat
    Updated (1):
  • firefoxPackages.tor-browser

• On x86_64-darwin:
  New (4):

  • firefoxPackages.icecat
  • firefoxPackages.tor-browser-7-5
  • firefoxPackages.tor-browser
  • icecat

Things done

• Built everything on x86_64-linux before rebasing to nixpkgs master

Note this also tries to enable tor-browser build on Darwin (because firefox has it enabled, so maybe it will work :]).

/cc @joachifm

[joachifm]

Thank you