fix github pulls json to be deterministic

Dependencies

• [2] 46VPIW3V Allow hydra-eval-jobset to be found by the hydra-evaluator
• [3] D5YPJDT6 Add GithubPulls input plugin.
• [4] L62I7CPI Don't put ssmtp in hydra's paths
• [5] ZYEFL36Q Ported/merged properties from the TUD configuration's hydra-module
• [6] EE5RRP3X hydra-module.nix: Make services require hydra-init
• [7] HRFFN34B Fix email notification
• [8] RS7WV4MY Remove ssmtp from $PATH again
• [9] FCNC325Z GithubPulls: Add 'revision' to the input
• [*] D3MDJONY

Change contents

• replacement in hydra-module.nix at line 344
  [4.2103]→[2.0:46](∅→∅)
  − path = [ pkgs.nettools cfg.package ];
  [4.2103]

  [4.2148]
  + path = with pkgs; [ nettools cfg.package jq ];
• replacement in src/lib/Hydra/Plugin/GithubPulls.pm at line 58
  [3.1941]→[3.1941:1991](∅→∅)
  − my $storePath = `nix-store --add "$filename"`
  [3.1941]

  [3.1991]
  + system("jq -S . < $filename > $tempdir/github-pulls-sorted.json");

  + my $storePath = `nix-store --add "$tempdir/github-pulls-sorted.json"`