Add IDocumentExecutor interface and DocumentExecutor class

Introduces the `IDocumentExecutor` interface with a method
`CreateDocumentAsync` for asynchronous document creation.
Implements the `DocumentExecutor` class that inherits from
`SQLExecutor`, providing the functionality to create documents
using a SQL connection and handle potential errors during
the process.

EnvelopeGenerator.Application/Contracts/SQLExecutor/IDocumentExecutor.cs

@@ -0,0 +1,18 @@
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IDocumentExecutor
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="base64"></param>
+    /// <param name="envelope_uuid"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<EnvelopeDocument> CreateDocumentAsync(string base64, string envelope_uuid, CancellationToken cancellation = default);
+}

EnvelopeGenerator.Infrastructure/Executor/DocumentExecutor.cs

@@ -0,0 +1,28 @@
+using Dapper;
+using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using EnvelopeGenerator.Application.SQL;
+using EnvelopeGenerator.Domain.Entities;
+using Microsoft.Data.SqlClient;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace EnvelopeGenerator.Infrastructure.Executor;
+
+public class DocumentExecutor : SQLExecutor, IDocumentExecutor
+{
+    public DocumentExecutor(IServiceProvider provider, IOptions<SQLExecutorParams> sqlExecutorParamsOptions) : base(provider, sqlExecutorParamsOptions)
+    {
+    }
+
+    public async Task<EnvelopeDocument> CreateDocumentAsync(string base64, string envelope_uuid, CancellationToken cancellation = default)
+    {
+        using var connection = new SqlConnection(Params.ConnectionString);
+        var sql = Provider.GetRequiredService<DocumentCreateReadSQL>();
+        await connection.OpenAsync(cancellation);
+        var parameters = DocumentCreateReadSQL.CreateParmas(base64, envelope_uuid);
+        var documents = await connection.QueryAsync<EnvelopeDocument>(sql.Raw, parameters);
+        return documents.FirstOrDefault()
+            ?? throw new InvalidOperationException($"Document creation failed. Parameters:" +
+            $"base64={base64}, envelope_uuid='{envelope_uuid}'.");
+    }
+}