feat: handle errors in slave state

Moves logic of error handling to slave_state
from tx entity.

feat: add unexpected_sda tx signal

feat: add clear_buffer input to tx

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

chore: use integer instead of natural when with range

fix: make rx properly working

tests: add startstop condition detector tests, fix behavior

fix: bugs in address detector

fix: compilation errors

feat: add i2c slave state entity

feat: add i2c misc entities