add option to enable profiling of python integrations

Add new config option `integration_profiling` which enables [profiling](https://docs.datadoghq.com/profiler/enabling/python/#usage) of python integrations.

This has proven valuable several times already while troubleshooting performance issues so we're adding it as an option to have it available by default without requiring a custom build.

datadog_checks_base/datadog_checks/base/utils/__init__.py

@@ -1,6 +1,9 @@
 # (C) Datadog, Inc. 2018-present
 # All rights reserved
 # Licensed under a 3-clause BSD style license (see LICENSE)
+import os
+
+from ..config import is_affirmative
 
 try:
     import datadog_agent
@@ -15,6 +18,12 @@
         else:
             patch(requests=True)
 
+    if is_affirmative(datadog_agent.get_config('integration_profiling')):
+        from ddtrace.profiling import Profiler
+
+        prof = Profiler(service='datadog-agent-integrations')
+        prof.start()
+
 except ImportError:
-    # Tracing Integrations is only available with Agent 6
+    # Tracing & profiling Integrations is only available with Agent 6
     pass