add conversational memory for RAG

[K-Schubert]

Description

Keep track of k messages in chat history for RAG.

Proposed changes

• Only track last k RAG requests?
• Track all last k messages (mix of autocomplete/RAG)?
• Implement user sessions (with user ID, auth token) to store chats in sessions, and display history? --> Otherwise chat history might be "mixed" between users if multiple requests are made at the same time.

@tabee we should discuss these features.

[tabee]

• --> Otherwise chat history might be "mixed" between users if multiple requests are made at the same time.

What you think about:

Session-based Authentication" or "Token-based Session Management.

1. Session ID Generation When the app is opened, a random session ID is generated, e.g., a string of 5 letters. This session ID is displayed to the user and stored in the app.
2. Storing Chat Data The chat data is stored in a database under the generated session ID. Each chat message is linked to this session ID.
3. Loading an Existing Session If a user wants to load an existing session, they enter the 5-letter session ID. The app then loads the corresponding chat data from the database.