driver: add rs485 half duplex interface support to uart driver (add jobs into *.yml file)

An existing UART driver does not support RS485 half duplex mode.
This task adds this functionality to ESP_IDF UART driver.
driver/uart.c/h: updated to add support of RS485 half duplex mode
examples/peripherals/uart_echo_rs485/main/rs485_example.c: added test example
components/driver/test/test_uart.c: added test of RS485 half duplex mode
docs/en/api-reference/peripherals/uart.rst: updated documentation
test_uart.c: suppress GCC warnings about discarded const qualifiers
uart.rst: remove sphinx warning - "Duplicate explicit target name"
simple change in uart.h file
update (test_uart.c) after rebase from master
update uart.rst, uart.c, rs485_example.c
Update example description in file Readme.md
update uart.c/h, uart.rst, test_uart.c according to review results
update uart.h (uart_set_rx_timeout() description
test_uart.c remove ignore tag

The tests are completed using RS485 adapters hardware connected to two ESP32 WROVER KITs.

TW#13812
Closes https://github.com/espressif/esp-idf/pull/667
Closes https://github.com/espressif/esp-idf/pull/1006

.gitlab-ci.yml

@@ -824,6 +824,24 @@ UT_001_31:
   tags:
     - ESP32_IDF
     - UT_T1_1
+    
+UT_001_32:
+  <<: *unit_test_template
+  tags:
+    - ESP32_IDF
+    - UT_T1_1
+
+UT_001_33:
+  <<: *unit_test_template
+  tags:
+    - ESP32_IDF
+    - UT_T1_1
+    
+UT_001_34:
+  <<: *unit_test_template
+  tags:
+    - ESP32_IDF
+    - UT_T1_1
 
 UT_002_01:
   <<: *unit_test_template
@@ -931,6 +949,13 @@ UT_004_10:
     - UT_T1_1
     - psram
     
+UT_004_11:
+  <<: *unit_test_template
+  tags:
+    - ESP32_IDF
+    - UT_T1_1
+    - psram
+    
 UT_005_01:
   <<: *unit_test_template
   tags: