Implement BossPvP logic (I implemented this based on undownding's code. Thank you!)

Common/Data/Excel/BossPvpNumExcel.cs

@@ -0,0 +1,15 @@
+namespace MikuSB.Data.Excel;
+
+[ResourceEntity("challenge/bosspvp/num.json")]
+public class BossPvpNumExcel : ExcelResource
+{
+    public uint Week { get; set; }
+    public uint Num { get; set; }
+
+    public override uint GetId() => Week;
+
+    public override void Loaded()
+    {
+        GameData.BossPvpNumData[Week] = this;
+    }
+}