Tests for `Board` methods

[ryan597]

Implement test cases for the following

• Default Constructor Board::Board()
• Fischer Random Constructor Board::Board(960)
• FEN: get, set, validate, print fen
• Print position from a given FEN Board::print_position(fen)
• Print current position from pieces Board::print()
• Check if given move is legal Board::is_legal_move
• Check moves are interpreted correctly (setup different FENs and test multiple different types of moves) Board::move()
• Check parsing Board::parse_move()
• Check pieces are initialized Board::get_pieces()