Fix Board::move() and Board::parse_move() to find src square

[ryan597]

Describe the bug
Currently parse_move doesn't find the source square for the move, and just moves the first matching piece type

To Reproduce

#include "board.cpp"
#include "player.cpp"

auto main(int argc, char** argv) -> int {
    Board board{};
    board.print();
    board.move("d4");
    board.print();
}

Expected behavior
Above should move the pawn on d2 to d4 by checking which pawns can legally move there.
generate_legal_moves will need to be implemented to allow checking of the pieces legal moves.

Additional context

Error logs

Dump error logs here