AAP-40782 Fix too-low max_workers value, dump running at capacity (#15873)

* Dump running tasks when running out of capacity

* Use same logic for max_workers and capacity

* Address case where CPU capacity is the constraint

* Add a test for correspondence

* Fake redis to make tests work

tools/scripts/firehose_tasks.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+from django import setup
+
+from awx import prepare_env
+
+prepare_env()
+
+setup()
+
+# Keeping this in test folder allows it to be importable
+from awx.main.tests.data.sleep_task import sleep_task
+
+
+for i in range(634):
+    sleep_task.delay()