Replaced PKCS#11-based cryptographic operations with a new DocumentService API integration. Removed all PKCS#11-related code, configurations, and dependencies, including options, self-test status, and signing logic. Updated `FinalizeEnvelopeCommand` to include a notification service and added base64 conversion for documents. Updated `ServiceCollectionExtensions` to register the new DocumentService client. Removed outdated documentation and diagrams related to PKCS#11. Updated project files and configurations to reflect these changes and incremented the version number. Added a comment in `EnvelopeFinalizationWorker` for future RabbitMQ integration.
Replaced "EnvelopeGenerator.WebUI" with "EnvelopeGenerator.Server" and "EnvelopeGenerator.WebUI.Client" with "EnvelopeGenerator.Server.Client". Updated project entries, solution configuration platforms, and nested projects to reflect these changes.
