Updated some namespaces, finished some todos. v5 should be cancelled probably as the code is too intertwined to make it modular

src/Nadeko.Common/Extensions/ArrayExtensions.cs

@@ -1,4 +1,6 @@
-namespace Nadeko.Common;
+using System.Security.Cryptography;
+
+namespace Nadeko.Common;
 
 // made for expressions because they almost never get added
 // and they get looped through constantly
@@ -48,4 +50,13 @@ public static class ArrayExtensions
 
         return toReturn;
     }
+
+    public static T? RandomOrDefault<T>(this T[] data)
+    {
+        if (data.Length == 0)
+            return default;
+
+        var index = RandomNumberGenerator.GetInt32(0, data.Length);
+        return data[index];
+    }
 }