Replace Mock Storage with SQLite Database Integration

[undefdev]

To enhance the functionality of the SimpleX Chat library and align it with real-world scenarios, we should replace the current mock storage system with an SQLite database. This will allow for persistent storage of messages, profiles, and other relevant data.

• Implement an SQLite database schema that matches the storage requirements of the SimpleX Chat protocol.
• Ensure compatibility with the SQLite database structure of the official Haskell client.
• Update all database-related operations in the library (e.g., message storage, profile management) to use the SQLite database.
• Test the new SQLite integration thoroughly to ensure data integrity, compatibility, and performance.