clear-queue-non-current: Work around PostgreSQL query optimizer stupidity

Dependencies

• [2] UOINKJ2J Add an action to cancel all builds in a jobset eval
• [3] 67NFGL7D add links in admin page to clear queue (all non-running builds, and all non-running old (non-current) builds)
• [4] R6B5CAFF Let Builds.timestamp refer to the time the build was added
• [5] DETQRBBR clear_queue_non_current: Don't use isCurrent
• [*] ZWCTAZGL added newsitems, added some admin options to clear various caches.

Change contents

• replacement in src/lib/Hydra/Controller/Admin.pm at line 38
  [2.50]→[3.37:239](∅→∅),[3.37]→[3.37:239](∅→∅)
  − { finished => 0, busy => 0

  − , id => { -not_in => \ "select build from JobsetEvalMembers where eval in (select max(id) from JobsetEvals where hasNewBuilds = 1 group by project, jobset)" }
  [2.50]

  [2.51]
  + { id => { -in => \ "select id from Builds where id in ((select id from Builds where finished = 0 and busy = 0) except (select build from JobsetEvalMembers where eval in (select max(id) from JobsetEvals where hasNewBuilds = 1 group by project, jobset)))" }