Added new art, also added stairs and walls to building menu

Assets/Scripts/Game/Buildings/Building.cs

@@ -0,0 +1,13 @@
+using UnityEngine;
+
+namespace Fruitomation.Game
+{
+    public class Building : MonoBehaviour
+    {
+        [Header("Building Properties")]
+        [SerializeField] private Sprite BuildingSprite;
+        [field: SerializeField] public Vector2Int SizeOnGrid { get; private set; }
+        
+        public Sprite Sprite => BuildingSprite;
+    }
+}