~ruther/vhdl-i2c

ref: b9b3fcea757ffdf6e98f0bb550606e38642635e6 vhdl-i2c/src/mcu_slave d---------
tests: add possibility to check sda stability in mcu_slave
tests: add mcu tests working with slave top designs
chore: fix slave naming in mcu slave designs
feat: add counter and register testing slave top levels