Add a root logger to the fedmsg base logging config

This alters the logging configuration for all fedmsg applications. It
adds a root logger configuration which handles messages that are not
covered by other loggers (and which also have ``propagate=False``). This
means that all Python modules will now be able to emit log messages,
rather than those in the ``fedmsg`` or ``moksha`` Python packages (or
other packages that use their loggers).

Signed-off-by: Jeremy Cline <jeremy@jcline.org>

roles/fedmsg/base/templates/logging.py.j2

@@ -237,5 +237,11 @@ config = dict(
                 "handlers": ["console", "mailer"],
             },
         ),
+        # Root handler that deals with log messages that are not handled by the
+        # loggers explicitly configured in the `loggers` dict.
+        root={
+            "level": "{{fedmsg_loglevel}}",
+            "handlers": ["console", "mailer"],
+        },
     ),
 )