general: Rename NewUUID to UUID, and remove the previous UUID impl

This completes the removal of the old UUID implementation.

src/input_common/drivers/touch_screen.cpp

@@ -8,7 +8,7 @@
 namespace InputCommon {
 
 constexpr PadIdentifier identifier = {
-    .guid = Common::NewUUID{},
+    .guid = Common::UUID{},
     .port = 0,
     .pad = 0,
 };