Added metadata for custom properties

src/main/java/META-INF/additional-spring-configuration-metadata.json

@@ -1,5 +1,15 @@
 {"properties": [{
   "name": "chatto.token.timeout-duration",
   "type": "java.lang.String",
-  "description": "A description for 'chatto.token.timeout-duration'"
+  "description": "The duration for auth token validity. Token expires after this period of inactivity"
+},
+{
+  "name": "chatto.frontend.log-level",
+  "type": "java.lang.String",
+  "description": "The log level for the frontend JS application"
+},
+{
+  "name": "chatto.frontend.chat-page-size",
+  "type": "java.lang.Integer",
+  "description": "The pagination size for the chat area"
 }]}