Adds Argon2 for password protection (#123)

Projects/Argon2/Argon2Context.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Server.Accounting.Security
+{
+  [StructLayout(LayoutKind.Sequential)]
+  internal class Argon2Context
+  {
+    public IntPtr Out;
+    public uint OutLen;
+
+    public IntPtr Pwd;
+    public uint PwdLen;
+
+    public IntPtr Salt;
+    public uint SaltLen;
+
+    public IntPtr Secret;
+    public uint SecretLen;
+
+    public IntPtr AssocData;
+    public uint AssocDataLen;
+
+    public uint TimeCost;
+    public uint MemoryCost;
+    public uint Lanes;
+    public uint Threads;
+
+    public IntPtr AllocateCallback;
+    public IntPtr FreeCallback;
+
+    public uint Flags;
+  }
+}