Adding the ability to disable full text search queries for master (#6102)

config/config.json

@@ -41,6 +41,7 @@
         "AllowEditPost": "always",
         "PostEditTimeLimit": 300,
         "TimeBetweenUserTypingUpdatesMilliseconds": 5000,
+        "EnablePostSearch": true,
         "EnableUserTypingMessages": true,
         "ClusterLogTimeoutMilliseconds": 2000
     },