Initialize repository

Added basic info to get in game for like...August 2016 ;-;
It's not much but it's a start

RecRoomArchive.Models/API/Config/LevelProgressionMap.cs

@@ -0,0 +1,10 @@
+using System.Text.Json.Serialization;
+
+namespace RecRoomArchive.Models.API.Config
+{
+    public class LevelProgressionMap(int level, int requiredXp)
+    {
+        [JsonPropertyName(name: "Level")] public int Level { get; set; } = level;
+        [JsonPropertyName(name: "RequiredXp")] public int RequiredXp { get; set; } = requiredXp;
+    }
+}