Add PKCS#11-based PDF signing infrastructure

Introduced a cryptographic infrastructure for PDF signing and validation using PKCS#11-based hardware security modules (HSMs) or software tokens. Key changes include:

- Added `PdfDigitalSignatureService` for signing PDFs, multi-signature support, and signature validation.
- Implemented `Pkcs11ExternalSigner` and `Pkcs11PdfSigningRsa` for PKCS#11-based signing with DevExpress PDF infrastructure.
- Added utilities like `Pkcs11SessionRunner`, `Pkcs11InteropBootstrap`, and `Pkcs11ToolBridge` for session management, library initialization, and fallback mechanisms.
- Introduced `Pkcs11Options` for managing PKCS#11 configurations.
- Updated project dependencies to include `DevExpress.Document.Processor`, `System.Security.Cryptography.Pkcs`, and `Pkcs11Interop`.
- Enhanced error handling and fallback support for PKCS#11 operations.

These changes enable robust and extensible PDF signing capabilities with detailed signature metadata extraction and validation.

EnvelopeGenerator.Infrastructure.Crypt/DependencyInjection/ServiceCollectionExtensions.cs

@@ -0,0 +1,22 @@
+using EnvelopeGenerator.Application.Common.Configurations;
+using EnvelopeGenerator.Application.Common.Interfaces.Services;
+using EnvelopeGenerator.Infrastructure.Crypt.Services;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Options;
+
+namespace EnvelopeGenerator.Infrastructure.Crypt.DependencyInjection;
+
+public static class ServiceCollectionExtensions
+{
+    public static IServiceCollection AddCryptInfrastructure(this IServiceCollection services, IConfiguration configuration)
+    {
+        services
+            .AddOptions<Pkcs11Options>()
+            .Bind(configuration.GetSection(Pkcs11Options.SectionName))
+            .ValidateDataAnnotations()
+            .ValidateOnStart();
+        services.AddSingleton<IPdfDigitalSignatureService, PdfDigitalSignatureService>();
+        return services;
+    }
+}