Refactor: Remove internal persistence, add Redis helper, and update README
- Removed MySQL-based internal data persistence (DB, Conversation, ConversationDB).
- Made the library stateless by removing all internal storage logic.
- Updated Telegram.php version to 1.0.4.
- Added a Redis helper (enableRedis, getRedis) using predis/predis for optional shared Redis client access in commands.
- Updated README.md with instructions and examples for the new Redis helper.