thinkfan: cleanup
thinkfan: cleanup

- Remove the custom installPhase: upstream has added an install target
and it does a better job than we do

- Improve meta: description -> longDescription and add a short one

- Fix license: GPL3 -> GPL3+

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs