Enhance envelope receiver functionality and documentation

Updated IEnvelopeReceiverExecutor with XML comments for
AddEnvelopeReceiverAsync method and added necessary using
directives. Introduced XML documentation for CreateParameters
in EnvelopeReceiverAddReadSQL. Modified
AddEnvelopeReceiverAsync in EnvelopeReceiverExecutor to
accept individual parameters, improving clarity and usability.

EnvelopeGenerator.Application/Contracts/SQLExecutor/IEnvelopeReceiverExecutor.cs

@@ -1,8 +1,20 @@
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
 
 /// <summary>
 /// 
 /// </summary>
 public interface IEnvelopeReceiverExecutor
 {
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelope_uuid"></param>
+    /// <param name="emailAddress"></param>
+    /// <param name="salutation"></param>
+    /// <param name="phone"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> AddEnvelopeReceiverAsync(string envelope_uuid, string emailAddress, string salutation, string? phone = null, CancellationToken cancellation = default);
 }