tout_thr - move calculation and masking into hal layer update driver and uart_ll (add uart_ll_set_rx_tout)
move tout calculation into uart_ll
move calculation of time out in bit time for esp32s2 into low level uart_ll.h file
move uart_hal_get_symb_len() into hal
update set_rx_timeout() to warn user about incorrect value
update HAL, LL 1
fix uart_xx_set_rx_tout() to convert symbol time into bit time
update param description
update tout calculation in LL
update uart_hal_get_max_rx_timeout_thrd() and uart_ll_get_max_rx_timeout_thrd()
add support of modbus master ascii
rename base dir name of master and slave example to be mb_slave, mb_master to avoid conflict with sdio/slave example test
add Kconfig option to enable ASCII and RTU mode separately
update ASCII options + remove cast for errors
added baudrate for examples into Kconfig
updated magic numbers for timer timeout
put ascii private definitions into one file
