Add recursive comparison to Array and Dictionary

...and expose it to GDScript.

Co-authored-by: Emmanuel Leblond <emmanuel.leblond@gmail.com>

modules/gdscript/gdscript_functions.h

@@ -126,6 +126,7 @@ public:
 		INSTANCE_FROM_ID,
 		LEN,
 		IS_INSTANCE_VALID,
+		DEEP_EQUAL,
 		FUNC_MAX
 	};