feat(shared): add string utils

Add utilities to convert a string to base64 and vice versa

src/Shared/Domain/Utils.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Text;
+
+namespace Armory.Shared.Domain
+{
+    public static class Utils
+    {
+        public static string StringToBase64(string str)
+        {
+            return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
+        }
+
+        public static string Base64ToString(string str)
+        {
+            return Encoding.UTF8.GetString(Convert.FromBase64String(str));
+        }
+    }
+}