task_queues: Add more scaffolding

appengine/swarming/cron.yaml

Index: appengine/swarming/cron.yaml
diff --git a/appengine/swarming/cron.yaml b/appengine/swarming/cron.yaml
index 057a87206ce0632e31528c09bc487caedcd8a79e..04a477dceda3d3df2928160013fe17e866cc5d37 100644
--- a/appengine/swarming/cron.yaml
+++ b/appengine/swarming/cron.yaml
@@ -21,14 +21,20 @@ cron:
   schedule: every 1 minutes
   target: backend
 
-- description: Compute Machine Provider bot utilization.
-  url: /internal/cron/machine_provider_bot_usage
-  schedule: every 1 minutes
+- description:
+    Clean up stale BotTaskDimensions and TaskDimensions so no composite indexes are needed.
+  url: /internal/cron/task_queues_tidy
+  schedule: every 10 minutes
   target: backend
 
 
 ### MP
 
+- description: Compute Machine Provider bot utilization.
+  url: /internal/cron/machine_provider_bot_usage
+  schedule: every 1 minutes
+  target: backend
+
 - description: Configure Machine Provider leases.
   url: /internal/cron/machine_provider_config
   schedule: every 1 minutes