Support permission api for bluetooth devices

[daphtdazz]

As per: https://webbluetoothcg.github.io/web-bluetooth/#permission-api-integration

Basically as I understand it this would allow web pages not to need to re-ask for permission to access devices they've requested permission to access before, making for a better experience for the user.

[murkle]

I've tested this in Chrome, works nicely https://docs.google.com/document/d/1RF4D-60cQJWR1LoQeLBxxigrxJwYS8nLOE0qWmBF1eo/edit