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()

TactilityKernel/Source/drivers/i2c_controller.cpp

@@ -49,7 +49,7 @@ error_t i2c_controller_has_device_at_address(Device* device, uint8_t address, Ti
     return I2C_DRIVER_API(driver)->write(device, address, message, 2, timeout);
 }
 
-extern const struct DeviceType I2C_CONTROLLER_TYPE {
+const struct DeviceType I2C_CONTROLLER_TYPE {
     .name = "i2c-controller"
 };