1- Creation of public class Coordinate.
2- Creation of Side and Symbols enumerations.
3- Creation of abstract class Piece.
4- Creation of final classes extending from abstract class Piece:
   -- public final classe Bishop.
   -- public final classe King.
   -- public final classe Knight.
   -- public final classe Pawn.
   -- public final classe Queen.
   -- public final classe Rook.
5- Initial Pawn movement logic has been added.