Uart improvments (#1024)

* uart: Add support for specifying the number of bits and parity.

ESP8266SwSerial doesn't really check parity but just read the parity bit
and ignore it when receiving data.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: support begin and end methods.

A component may need to reset uart buffer/status by using begin() and
end() methods. This is useful for example when a component needs to be
sure it is not reading garbage from previously received data over uart.
For end() methods with software serial, disabling interrupt is
currently impossible because of a bug in esp8266 Core:
https://github.com/esp8266/Arduino/issues/6049

Signed-off-by: 0hax <0hax@protonmail.com>

* esphal: add support for detaching an interrupt.

That's needed when a component needs to enable/disable interrupt on a
gpio.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: rename CONF_NR_BITS to CONF_DATA_BITS_NUMBER.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: use static const uint32_t instead of #define.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: use an enum to handle parity.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: split between esp32 and esp8266.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: check_uart_settings for parity and number of data bits.

Signed-off-by: 0hax <0hax@protonmail.com>

* name param data_bits

* add new params to test

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

tests/test1.yaml

@@ -132,6 +132,9 @@ uart:
   rx_pin: GPIO23
   baud_rate: 115200
   id: uart0
+  parity: NONE
+  data_bits: 8
+  stop_bits: 1
 
 ota:
   safe_mode: True