hydra: order machines by enabled/disabled, add green and red color for enabled/disabled

Dependencies

• [2] SMCOU72F hydra: add some admin for adding/enabling/etc build machines
• [3] QT4FO2HP refactored admin controller, using chains, to avoid using requireadmin on each endpoint
• [4] ZWCTAZGL added newsitems, added some admin options to clear various caches.

Change contents

• replacement in src/lib/Hydra/Controller/Admin.pm at line 48
  [2.994]→[2.994:1027](∅→∅)
  − { order_by => "hostname"
  [2.994]

  [2.1027]
  + { order_by => ["enabled DESC", "hostname"]
• replacement in src/root/admin.tt at line 23
  [2.9550]→[2.9550:9579](∅→∅)
  − <th colspan="5">
  [2.9550]

  [2.9579]
  + <th colspan="5" style="background-color: [% IF m.enabled == 1 %]lime[% ELSE %]red[% END %];">