wayland: implement ext-foreign-toplevel-list-v1

wire/ext_foreign_toplevel_list_v1.txt

@@ -0,0 +1,16 @@
+# requests
+
+msg stop = 0 {
+}
+
+msg destroy = 1 {
+}
+
+# events
+
+msg toplevel = 0 {
+    toplevel: id(ext_foreign_toplevel_handle_v1),
+}
+
+msg finished = 1 {
+}