add debug views for task manager(s)

implement https://github.com/ansible/awx/issues/12446
in development environment, enable set of views that run
the task manager(s).

Also introduce a setting that disables any calls to schedule()
that do not originate from the debug views when in the development
environment. With guards around both if we are in the development
environment and the setting, I think we're pretty safe this won't get
triggered unintentionally.

use MODE to determine if we are in devel env

Also, move test for skipping task managers to the tasks file

awx/api/urls/debug.py

@@ -0,0 +1,17 @@
+from django.urls import re_path
+
+from awx.api.views.debug import (
+    DebugRootView,
+    TaskManagerDebugView,
+    DependencyManagerDebugView,
+    WorkflowManagerDebugView,
+)
+
+urls = [
+    re_path(r'^$', DebugRootView.as_view(), name='debug'),
+    re_path(r'^task_manager/$', TaskManagerDebugView.as_view(), name='task_manager'),
+    re_path(r'^dependency_manager/$', DependencyManagerDebugView.as_view(), name='dependency_manager'),
+    re_path(r'^workflow_manager/$', WorkflowManagerDebugView.as_view(), name='workflow_manager'),
+]
+
+__all__ = ['urls']