Refactor envelope creation logic and SQL execution

- Changed `_sqlExecutor` type in `CreateEnvelopeCommandHandler` to non-generic `ISQLExecutor`.
- Updated `Handle` method to use `CreateEnvelopeAsync` for simplified parameter handling.
- Restructured `CreateEnvelopeSQL` to implement `ISQL<Envelope>` with a raw SQL command for creating envelopes.
- Added `SetDappeTypeMap<TModel>` method in `DependencyExtensions` for Dapper type mappings.
- Improved overall code structure for better separation of concerns and maintainability.

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs

@@ -1,9 +1,9 @@
 using AutoMapper;
 using Dapper;
 using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using EnvelopeGenerator.Application.SQL;
 using EnvelopeGenerator.Domain.Entities;
 using MediatR;
-using Microsoft.Data.SqlClient;
 
 namespace EnvelopeGenerator.Application.Envelopes.Commands;
 
@@ -12,7 +12,7 @@ namespace EnvelopeGenerator.Application.Envelopes.Commands;
 /// </summary>
 public class CreateEnvelopeCommandHandler : IRequestHandler<CreateEnvelopeCommand, CreateEnvelopeResponse?>
 {
-    private readonly ISQLExecutor<Envelope> _sqlExecutor;
+    private readonly ISQLExecutor _sqlExecutor;
 
     private readonly IMapper _mapper;
 
@@ -35,14 +35,10 @@ public class CreateEnvelopeCommandHandler : IRequestHandler<CreateEnvelopeComman
     /// <returns></returns>
     public async Task<CreateEnvelopeResponse?> Handle(CreateEnvelopeCommand request, CancellationToken cancellationToken)
     {
-        var parameters = new DynamicParameters();
-        parameters.Add("@UserId", request.UserId);
-        parameters.Add("@Title", request.Title);
-        parameters.Add("@TfaEnabled", request.TFAEnabled ? 1 : 0);
-        parameters.Add("@Message", request.Message);
+        int userId = request.UserId ?? throw new InvalidOperationException("UserId cannot be null when creating an envelope.");
 
-        var envelopes = await _sqlExecutor.Execute<Envelope, CreateEnvelopeSQL>(parameters, cancellationToken);
+        var envelope = await _sqlExecutor.CreateEnvelopeAsync<Envelope>(userId, request.Title, request.Message, request.TFAEnabled, cancellationToken);
 
-        return _mapper.Map<CreateEnvelopeResponse>(envelopes.FirstOrDefault());
+        return _mapper.Map<CreateEnvelopeResponse>(envelope);
     }
 }