Refactor EventHandles supervisord access to a mixin

lib/util.py

@@ -1,4 +1,6 @@
-import json
+import json, xmlrpc.client
+
+from config.envvars import SUPERVISOR_HTTP_URI
 
 
 def parse_anchor_from_message(message):
@@ -11,4 +13,7 @@ def create_source_code_response_data(filename, content, language):
         'filename': filename,
         'content': content,
         'language': language
-    }
+    }
+
+class SupervisorMixin:
+    supervisor = xmlrpc.client.ServerProxy(SUPERVISOR_HTTP_URI).supervisor