data tree REFACTOR opaq name and its module information structure

Put the node name and its module into a separate
structure to follow lyd_node's schema and the
information it stores.
diff --git a/tests/utests/data/test_new.c b/tests/utests/data/test_new.c
index c1fec03..9d59e50 100644
--- a/tests/utests/data/test_new.c
+++ b/tests/utests/data/test_new.c
@@ -203,15 +203,15 @@
     assert_int_equal(lyd_new_opaq(NULL, ctx, "node1", NULL, "my-module", &root), LY_SUCCESS);
     assert_null(root->schema);
     opq = (struct lyd_node_opaq *)root;
-    assert_string_equal(opq->name, "node1");
-    assert_string_equal(opq->prefix.module_name, "my-module");
+    assert_string_equal(opq->name.name, "node1");
+    assert_string_equal(opq->name.module_name, "my-module");
     assert_string_equal(opq->value, "");
 
     assert_int_equal(lyd_new_opaq(root, NULL, "node2", "value", "my-module2", &node), LY_SUCCESS);
     assert_null(node->schema);
     opq = (struct lyd_node_opaq *)node;
-    assert_string_equal(opq->name, "node2");
-    assert_string_equal(opq->prefix.module_name, "my-module2");
+    assert_string_equal(opq->name.name, "node2");
+    assert_string_equal(opq->name.module_name, "my-module2");
     assert_string_equal(opq->value, "value");
     assert_ptr_equal(opq->parent, root);