Add config setting to disable statuses (#6254)

config/config.json

@@ -43,6 +43,7 @@
         "TimeBetweenUserTypingUpdatesMilliseconds": 5000,
         "EnablePostSearch": true,
         "EnableUserTypingMessages": true,
+        "EnableUserStatuses": true,
         "ClusterLogTimeoutMilliseconds": 2000
     },
     "TeamSettings": {