Add new items to the list of accepted CORS origins

[Xayton]

The Arduino Agent might be used in some pages that will be hosted on new third-level domains.
https://github.com/arduino/arduino-create-agent/blob/main/main.go#L362-L366

Needed changes:

• remove the previously added register.arduino.cc (Add register.arduino.cc to the list of accepted CORS origins #908)
• add the new board-registration.arduino.cc
• add a new wildcard item, to cover all the following fourth-level domains: *.app.arduino.cc