Refactor packages and add exception handler.

Renamed various classes to follow the "controlers" package structure for better organization and consistency. Added `ControllerExceptionHandler` to manage validation exceptions globally and improve error logging.

src/main/java/com/alttd/forms/verify_mail/FormQuery.java

@@ -1,6 +1,6 @@
 package com.alttd.forms.verify_mail;
 
-import com.alttd.forms.contact.ContactFormData;
+import com.alttd.forms.controlers.contact.ContactFormData;
 import com.alttd.forms.database.DatabaseConnection;
 import com.alttd.forms.form.Form;
 import com.fasterxml.jackson.core.JsonProcessingException;