Resolve "Add option to disable `REQUEST AN ACCOUNT`"

Closes #626 (closed)

model/src/main/java/lcsb/mapviewer/model/user/ConfigurationElementType.java

@@ -79,7 +79,7 @@ public enum ConfigurationElementType {
   /**
    * Email used for requesting an account (in client side).
    */
-  REQUEST_ACCOUNT_EMAIL("Email used for requesting an account", "your.email@domain.com",
+  REQUEST_ACCOUNT_EMAIL("Email used for requesting an account", "",
       ConfigurationElementEditType.EMAIL, false, ConfigurationElementTypeGroup.EMAIL_NOTIFICATION),
 
   /**