Add kernel drivers for SPI and UART and make locking APIs more consistent (#489)

- Add kernel support for SPI driver
- Add kernel support for UART driver
- Implemented ESP32 UART kernel driver
- Update existing UART-related code in Tactility to use new kernel driver
- Remove UART from tt::hal::Configuration
- Remove tt_hal_uart functionality but keep functions for now
- Update devicetrees for UART changes
- Kernel mutex and recursive mutex: improved locking API design
- Other kernel improvements
- Added device_exists_of_type() and device_find_by_name()

TactilityC/Include/tt_hal_uart.h

@@ -9,6 +9,13 @@
 extern "C" {
 #endif
 
+/**
+ * !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+ * WARNING: THIS API IS NON-FUNCTIONAL AND DEPRECATED.
+ * IT WILL BE REMOVED IN A FUTURE RELEASE ONCE OFFICIAL APPS ARE MIGRATED.
+* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+ */
+
 /**
  * @file tt_hal_uart.h
  * @brief C HAL interface for UART devices used by Tactility C modules.