Use WebUSB fallback when serial is not available

[sverben]

Whenever webserial is not available we should fallback to webusb to support a wider range of browsers including several Android browsers, see compatibility table

We can do this by using Google's WebSerial polyfill for WebUSB, the API should be (almost) fully compatible with the WebSerial API

Although limited to robot's that have an USB chip, this will allow Android devices to use the Leaphy software. The generic UNO and Nano do not support this functionality, the Nano ESP32 and Nano RP2040 do support this.

[sverben]

early version appears to be working for all arduino's including generic ones, under the condition that there is no serial driver for the device available, which aren't present on Android