Fix colspan

Dependencies

• [2] RFGPN7U7 Machine status: Don't show removed machines anymore
• [3] HTL6HIBM machine-status: Read /etc/nix.machines instead of using the BuildMachines table
• [4] V6S6OYIA Formatting tweaks
• [5] J4R2VCPP Fix showing build steps in the machine status page
• [*] ZWCTAZGL added newsitems, added some admin options to clear various caches.

Change contents

• replacement in src/root/machine-status.tt at line 45
  [3.1730]→[2.434:546](∅→∅)
  − <tr><td colspan="5">Idle for [% INCLUDE renderDuration duration = curTime - m.value.idle %]</td></tr>
  [3.1730]

  [3.1844]
  + <tr><td colspan="6">Idle for [% INCLUDE renderDuration duration = curTime - m.value.idle %]</td></tr>
• replacement in src/root/machine-status.tt at line 47
  [3.1863]→[3.613:664](∅→∅)
  − <tr><td colspan="5">Never used</td></tr>
  [3.1863]

  [3.1915]
  + <tr><td colspan="6">Never used</td></tr>