Allow the cdn in listen button link cms manageable

Thanks @enyug, great work! However, there is already an issue about updating the script and adding a region option. So it's probably best to take care of both things at the same time. With a basis in you great work, I changed the region setting to be on the main form and not the individual blocks. Maybe we can discuss if it should be on the main form or block in 📌 Update script and listen button URL's Fixed ? If you agree, feel free to close this issue as a duplicate, and we can make sure you get credited in the other issue for your great effort here.

Let's continue over in the other issue :)