folding@home: 6.02 -> 7.5.1

The v7 series is very different.

This commit introduces the 3 packages: fahclient, fahcontrol and
fahviewer. It also rebuilds the NixOS module to map better with the new
client.

nixos/modules/services/misc/folding-at-home.nix

@@ -1,67 +0,0 @@
-{ config, lib, pkgs, ... }:
-with lib;
-let
-  stateDir = "/var/lib/foldingathome";
-  cfg = config.services.foldingAtHome;
-  fahUser = "foldingathome";
-in {
-
-  ###### interface
-
-  options = {
-
-    services.foldingAtHome = {
-
-      enable = mkOption {
-        default = false;
-        description = ''
-          Whether to enable the Folding@Home to use idle CPU time.
-        '';
-      };
-
-      nickname = mkOption {
-        default = "Anonymous";
-        description = ''
-          A unique handle for statistics.
-        '';
-      };
-
-      config = mkOption {
-        default = "";
-        description = ''
-          Extra configuration. Contents will be added verbatim to the
-          configuration file.
-        '';
-      };
-
-    };
-
-  };
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-
-    users.users.${fahUser} =
-      { uid = config.ids.uids.foldingathome;
-        description = "Folding@Home user";
-        home = stateDir;
-      };
-
-    systemd.services.foldingathome = {
-      after = [ "network.target" ];
-      wantedBy = [ "multi-user.target" ];
-      preStart = ''
-        mkdir -m 0755 -p ${stateDir}
-        chown ${fahUser} ${stateDir}
-        cp -f ${pkgs.writeText "client.cfg" cfg.config} ${stateDir}/client.cfg
-      '';
-      script = "${pkgs.su}/bin/su -s ${pkgs.runtimeShell} ${fahUser} -c 'cd ${stateDir}; ${pkgs.foldingathome}/bin/fah6'";
-    };
-
-    services.foldingAtHome.config = ''
-        [settings]
-        username=${cfg.nickname}
-    '';
-  };
-}