refactor(Extension): move to Application.Extensions and remove the project.

- update references

EnvelopeGenerator.Application/Extensions/EncodingExtensions.cs

@@ -0,0 +1,30 @@
+using Microsoft.Extensions.Logging;
+using System.Text;
+
+namespace EnvelopeGenerator.Application.Extensions
+{
+    /// <summary>
+    /// Provides extension methods for decoding and extracting information from an envelope receiver ID.
+    /// </summary>
+    public static class EncodingExtensions
+    {
+        public static string EncodeEnvelopeReceiverId(this long readOnlyId)
+        {
+            //The random number is used as a salt to increase security but it is not saved in the database.
+            string combinedString = $"{Random.Shared.Next()}::{readOnlyId}::{Random.Shared.Next()}";
+            byte[] bytes = Encoding.UTF8.GetBytes(combinedString);
+            string base64String = Convert.ToBase64String(bytes);
+
+            return base64String;
+        }
+
+        public static string EncodeEnvelopeReceiverId(this (string envelopeUuid, string receiverSignature) input)
+        {
+            string combinedString = $"{input.envelopeUuid}::{input.receiverSignature}";
+            byte[] bytes = Encoding.UTF8.GetBytes(combinedString);
+            string base64String = Convert.ToBase64String(bytes);
+
+            return base64String;
+        }
+    }
+}