UART refactored (#236)

`Uart` is now an abstract class with a `UartEsp` and a `UartPosix` implementation.

TactilityHeadless/Private/Tactility/hal/gps/GpsInit.h

@@ -2,6 +2,8 @@
 
 #include "Tactility/hal/gps/GpsDevice.h"
 
+namespace tt::hal::uart { class Uart; }
+
 namespace tt::hal::gps {
 
 /**
@@ -14,6 +16,6 @@ bool init(const std::vector<GpsDevice::Configuration>& configurations);
 /**
  * Init sequence on UART for a specific GPS model.
  */
-bool init(uart_port_t port, GpsModel type);
+bool init(uart::Uart& uart, GpsModel type);
 
 }