feat!: Expanded add_methods to extra_user_data

Instead of being a function it now expects a struct with the
PartialUserData trait implemented. This in part ensures the correct
function signature.

It also adds another optional function to PartialUserData that returns
definitions for the added methods.

automation_lib/src/lua/traits.rs

@@ -8,6 +8,10 @@ pub trait PartialUserData<T> {
     fn interface_name() -> Option<&'static str> {
         None
     }
+
+    fn definitions() -> Option<String> {
+        None
+    }
 }
 
 pub struct Device;