Move data and data loading to plugin libraries.

PkmnLib.Dynamic/Libraries/DataLoaders/GrowthRateDataLoader.cs

@@ -0,0 +1,22 @@
+using System.Text.Json;
+using PkmnLib.Static;
+using PkmnLib.Static.Libraries;
+
+namespace PkmnLib.Dynamic.Libraries.DataLoaders;
+
+public static class GrowthRateDataLoader
+{
+    public static GrowthRateLibrary LoadGrowthRates(Stream stream, Action<List<IGrowthRate>>? action = null)
+    {
+        var objects = JsonSerializer.Deserialize<Dictionary<string, uint[]>>(stream, JsonOptions.DefaultOptions)!;
+        var growthRates = objects.Select(x => new LookupGrowthRate(x.Key, x.Value)).Cast<IGrowthRate>().ToList();
+        action?.Invoke(growthRates);
+
+        var library = new GrowthRateLibrary();
+        foreach (var growthRate in growthRates)
+        {
+            library.Add(growthRate);
+        }
+        return library;
+    }
+}