feat: handle errors in slave state

Moves logic of error handling to slave_state
from tx entity.

feat: add unexpected_sda tx signal

refactor: use 'H' std_logic state instead of custom pull up type

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

fix: activate pad_io in open drain on enable = 1

feat: add clear_buffer input to tx

fix: correct delay pulses length

fix: make slave work

feat: add slave top

feat: handle ack in rx, tx

feat(tx): remove unnecessary bit index

feat: add stateful sda, scl switch

chore: use process(all) for combinational processes

fix: tx bugs

feat(rx): make rx idle on start/stop condition

fix(rx): stretching behavior

refactor(rx): do not use unnecessary index