Make universal Arena.
Based on the previous discussion, a universal Arena class is introduced. Additional attributes (spawnPositionX, spawnPositionY, and spawnRotation) are defined, initialized in the constructor, and used in the spawn() and respawn(Enemy) methods. Attributes related to the arena's dimensions (width and height) are also defined and initialized in the constructor. As the Arena class serves as a blueprint for defining concrete arenas, it is defined as an abstract class.