Remove some redundant SQL queries

Dependencies

• [2] V6S6OYIA Formatting tweaks
• [3] HTL6HIBM machine-status: Read /etc/nix.machines instead of using the BuildMachines table
• [4] J4R2VCPP Fix showing build steps in the machine status page
• [5] SMCOU72F hydra: add some admin for adding/enabling/etc build machines
• [*] ZWCTAZGL added newsitems, added some admin options to clear various caches.

Change contents

• replacement in src/root/machine-status.tt at line 24
  [2.852]→[2.852:1006](∅→∅)
  − <td><tt>[% INCLUDE renderFullJobName project = step.build.project.name jobset = step.build.jobset.name job = step.build.job.name %]</tt></td>
  [2.852]

  [2.1006]
  + <td><tt>[% INCLUDE renderFullJobNameOfBuild build=step.build %]</tt></td>