Add AddReceiver method and refactor SQL classes

Introduced a new `AddReceiver` method in the `Extension` class to facilitate adding a receiver to an envelope. This method includes parameters for `envelope_uuid`, `emailAdress`, `salutation`, and an optional `phone`, along with XML documentation for clarity.

Removed the `EnvelopeReceiverCreateReadSQL` class and added the `EnvelopeReceiverAddReadSQL` class, which defines the SQL command for adding a receiver. The new class also includes XML documentation comments for better understanding.

EnvelopeGenerator.Application/Contracts/SQLExecutor/Extension.cs

@@ -29,4 +29,26 @@ public static class Extension
         var envelopes = await executor.Execute<Envelope, EnvelopeCreateReadSQL>(parameters, cancellation);
         return envelopes.FirstOrDefault();
     }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="executor"></param>
+    /// <param name="envelope_uuid"></param>
+    /// <param name="emailAdress"></param>
+    /// <param name="salutation"></param>
+    /// <param name="phone"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    public static async Task<EnvelopeReceiver?> AddReceiver(this ISQLExecutor executor, string envelope_uuid, string emailAdress, string salutation, string? phone = null, CancellationToken cancellation = default)
+    {
+        var parameters = new DynamicParameters();
+        parameters.Add("@ENV_UID", envelope_uuid);
+        parameters.Add("@EMAIL_ADRESS", emailAdress);
+        parameters.Add("@SALUTATION", salutation);
+        parameters.Add("@PHONE", phone);
+
+        var envelopeReceivers = await executor.Execute<EnvelopeReceiver, EnvelopeReceiverAddReadSQL>(parameters, cancellation);
+        return envelopeReceivers.FirstOrDefault();
+    }
 }

EnvelopeGenerator.Application/SQL/EnvelopeReceiverAddReadSQL.cs

@@ -6,7 +6,7 @@ namespace EnvelopeGenerator.Application.SQL;
 /// <summary>
 /// 
 /// </summary>
-public class EnvelopeReceiverCreateReadSQL : ISQL<Envelope>
+public class EnvelopeReceiverAddReadSQL : ISQL<Envelope>
 {
     /// <summary>
     ///