Add support for Web Bluetooth connection to device about addon-bluetooth-webgui HOT 1 OPEN

I think the current WebSerial together with a Bluetooth based serial connection is no way, because it will never be supported on mobile devices (it would be the easiest option).

WebBluetooth does add Android to the list, but iOS is not working out of the box (you need to install a special browser):

https://developer.mozilla.org/en-US/docs/Web/API/Web_Bluetooth_API
http://www.espruino.com/Quick+Start+BLE (iOS)

Nevertheless, you are right, we should add WebBluetooth for mobile configuration possibility.

We need to implement an additional GATT characteristics to the currently used HID ones.
And this must be done for 2 different BT chipsets:

• PicoW with BTStack
• ESP32 with https://github.com/asterics/esp32_mouse_keyboard

The uart.js library looks like they are using the "Nordic UART service" behind the scenes, which means we need these UUIDs to be compatible with the library (otherwise it won't work):
https://github.com/espruino/EspruinoWebTools/blob/2ab71a33d69bfda40465174ffe57adb03c21fc42/uart.js#L117

Personally I really would like to have this feature, but I'm not sure when we should do that.
In addition, we need to adapt the firmwares in the controllers (FM3, FABI2, FABI3) a little bit to distinguish between
"serial" commands coming from the BT module or responses from the BT module to serial commands from USB-CDC.

from addon-bluetooth-webgui.