Restrict Gunicorn configuration output to debug

There's a `print()` command in gunicorn_conf.py that prints the custom
Gunicorn configuration not output by Gunicorn with `LOG_LEVEL="debug"`.

This commit will only run the `print()` command if `LOG_LEVEL="debug"`.

inboard/gunicorn_conf.py

@@ -69,5 +69,5 @@
     "errorlog": errorlog,
     "accesslog": accesslog,
 }
-
-print(f"[{Path(__file__).stem}] Additional configuration:", json.dumps(log_data))
+if loglevel == "debug":
+    print(f"[{Path(__file__).stem}] Custom configuration:", json.dumps(log_data))