data tree REFCTOR move prefix callbacks to plugins types

Meaning they are still public but needed only when
implementing plugins. Common API functions do not
require these callbacks.
diff --git a/src/validation.h b/src/validation.h
index d6d1f17..4f1c4c1 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -17,6 +17,7 @@
 
 #include "log.h"
 #include "parser_data.h"
+#include "plugins_types.h"
 #include "tree_data.h"
 
 /**