Integrate `UARTPort`

[thanasipantazides]

Status

There is a lovely UART interface here. It needs to be integrated in the flight software.

There are two other places UART-related work is done in the code.

1. A UART object holds limited, runtime-constant configuration data on the UART link.
2. TransportLayerMachine manages all the network operations onboard (Ethernet-to-Ethernet communication, Ethernet-to-buffer, SpaceWire-to-buffer, etc). This class will need to expose the UART interface implemented in UARTPort.

Todo

• [x] Kris think about a better naming scheme so UARTPort and UART are less confusing. Honestly UARTPort seems fine, it's UART that is totally generic and unclear.
• [ ] Kris add a new constructor to UARTPort that takes a reference to a UART, plus vtime argument (I think we initialize vmin as default then modify it on-the-fly using command-specific size data).
  • for background here, I generate UART objects from JSON configuration data on startup, so that's a convenient way to hand you the information.
• [x] Kris modify TransportLayer.h adding a field with a reference to a UARTPort and modifying each constructor:

  class TransportLayerMachine {
  // ...
  UARTPort& uart_port;
  TransportLayerMachine(... , UARTPort& port, boost::asio::io_context& context)
  // ...
  };

• [x] Kris modify TransportLayer.cpp implementing the TransportLayerMachine constructors. You should initializer TransportLayerMachine::uart_port using initializer list syntax as is done for the io_context objects.
• [x] Then, Thanasi add UART-specific methods to TransportLayerMachine.