JavaScript: Add I2C support

[jamisonderek]

What's new

• Adds the ability to interact with I2C devices (pins 15/16) using APIs for isDeviceReady, read, write and writeRead.
• Sample script uses inexpensive AT24C32 EEPROM for API demonstration (used in some SAO badges)
• Sample script writes some data at EEPROM address 0x0000, reads from 0x0001 and continues reading from 0x0004.

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For the reviewer

• I've uploaded the firmware with this patch to a device and verified its functionality
• I've confirmed the bug to be fixed / feature to be stable

[Willy-JL]

i'll get the arraybuf changes implemented myself, other feedback needs some discussion 😄

[Willy-JL]

@jamisonderek let me know what you think of the changes I made and please check if still works correctly (i dont have i2c devices to test), then if all is ok we can merge.

thanks!

[jamisonderek]

Works great, thanks for the improvements! I also verified it works using the Uint8Array as well for the tx data.

• i2c.write(addr, Uint8Array([0x00, 0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47]));
• let data_buf = i2c.writeRead(addr, Uint8Array([0x00, 0x01]), 3, 100);