Refactor agent and models for LiteLLM integration

[TerminallyLazy]

• Updated agent.py to include LiteLLM dependencies and improved serialization method.
• Refactored models.py to streamline model handling and added LiteLLM support.
• Enhanced memory.py for better document management and indexing.
• Updated Dockerfiles and docker-compose.yml to ensure LiteLLM is installed.
• Added model hints in settings.js and corresponding styles in settings.css for improved UI experience.
• Adjusted browser_agent.py to handle telemetry and ensure proper response handling.