maixbit: add basic integration tests

[yannishuber]

I made some tests for the MAix Bit which I am currently working on in TinyGo. I dont know if maybe you wish to add this board to TinyHCI, this would be a start :).

This PR depends on tinygo-org/drivers#163.

[deadprogram]

Hi @yannishuber this is great!

A few changes and additions that will be needed. First of all, the way that I get each device to mount all at the same time on a known port is by adding here: https://github.com/tinygo-org/tinyhci/blob/master/tools/udev/99-named-devices.rules

You will need to make change to tools/server/boards.go to make the port name you add to the udev file.

OK, next, need to add the flashing tool used for this board, and any dependencies, to the Dockerfile here https://github.com/tinygo-org/tinyhci/blob/master/tools/docker/Dockerfile so that the tests can be flashed onto the board during the check run.

Regarding the test itself, the reason I use the MPU-6050 for all of the I2C tests is that I have a lot of them, and having a single standardized peripheral makes it easier. You might not have one, so I can replace that code for testing if you want.

I also generally create a task in the Makefile so I can flash/run the tests separately just to verify they are working: https://github.com/tinygo-org/tinyhci/blob/master/Makefile#L44

[yannishuber]

@deadprogram I made the changes you requested. I don't have an MPU-6050 so yes you can make that change, thank you.