Use faster query to determine number of running builds

Dependencies

• [2] TPNHTE5V Remove obsolete Builds columns and provide accurate "Running builds"
• [3] EFWN7JBV * Added a status page that shows all the currently executing build steps.
• [4] K42RSSSI
• [5] HRAFVVOE make logo configurable via HYDRA_LOGO env var
• [6] MGOGOKQP add tracker html code via HYDRA_TRACKER
• [7] MOX7XJ2E Merge the BuildSchedulingInfo table into the Builds table
• [8] 2DHE2ZAK Allow Hydra to run as a private instance by requiring a login.
• [9] CQTN62OH Die tabs die
• [*] J5UVLXOK * Start of a basic Catalyst web interface.

Change contents

• replacement in src/lib/Hydra/Controller/Root.pm at line 48
  [3.54]→[2.851:1059](∅→∅)
  − $c->stash->{nrRunningBuilds} = $c->model('DB::Builds')->search(

  − { finished => 0, 'buildsteps.busy' => 1 },

  − { join => 'buildsteps', select => ["id"], distinct => 1 })->count();
  [3.54]

  [3.2622]
  + $c->stash->{nrRunningBuilds} = $c->model('DB')->schema->storage->dbh->selectrow_array(

  + "select count(distinct build) from buildsteps where busy = 1");