fix(pm/wiki): Correct poor maintenance behaviors

We're seeing some issues with jobs choking up when we have a
long-waiting maintenance service

Instead, we think it might be better to have this run every 30 seconds
for at most 30 seconds, thus causing stuck jobs not to cause trouble...

packetmix/systems/teal/wiki.nix

···
   systemd.timers.mediawiki-maintenance = {
     wantedBy = [ "timers.target" ];
     timerConfig = {
-      OnUnitActiveSec = "5min";
-      OnBootSec = "5min";
+      OnUnitActiveSec = "30";
+      OnBootSec = "30";
       Persistent = false;
       Unit = "mediawiki-maintenance.service";
     };
···
 
   systemd.services.mediawiki-maintenance = {
     script = ''
-      ${config.services.phpfpm.pools.mediawiki.phpPackage}/bin/php ${config.services.mediawiki.finalPackage}/share/mediawiki/maintenance/run.php runJobs --memory-limit 1G --wait
+      ${config.services.phpfpm.pools.mediawiki.phpPackage}/bin/php ${config.services.mediawiki.finalPackage}/share/mediawiki/maintenance/run.php runJobs --memory-limit 1G --maxtime 30
     '';
     serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = false;
       User = "mediawiki";
       Group = "nginx";
       PrivateTmp = true;