Add ApiExplorerSettings to DTOs and update controllers

This commit introduces the `[ApiExplorerSettings(IgnoreApi = true)]` attribute to various DTO classes to exclude them from API documentation. The `using Microsoft.AspNetCore.Mvc;` directive has been added to several files to support ASP.NET Core MVC features.

Additionally, comments in `HistoryController.cs` have been reformatted for clarity, and `LocalizationController.cs` has been updated with standard API controller attributes. These changes improve code organization and maintain cleaner API documentation.

EnvelopeGenerator.GeneratorAPI/Controllers/LocalizationController.cs

@@ -11,6 +11,7 @@ namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 /// <summary>
 /// Controller für die Verwaltung der Lokalisierung und Spracheinstellungen.
 /// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
 [Route("api/[controller]")]
 [ApiController]
 public class LocalizationController : ControllerBase