Revert "Refactor envelope handling to use ISQLExecutor"

This reverts commit 4cabaf3191.

EnvelopeGenerator.Application/Contracts/SQLExecutor/IEnvelopeExecutor.cs

@@ -0,0 +1,19 @@
+using Dapper;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IEnvelopeExecutor : ISQLExecutor
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="parameters"></param>
+    /// <param name="addUser"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<Envelope?> CreateEnvelopeAsync(DynamicParameters parameters, bool addUser = true, CancellationToken cancellation = default);
+}