feat(graphiti): Define entity and edge types in new graphiti_schema for structured data extraction
feat(graphiti): Enhance ingest_episode_event_step with schema integration for improved episode processing
- Added `graphiti_client.py` to manage the Graphiti client as a singleton.
- Created `ingest_episode_event_step.py` to handle episode ingestion from HTTP webhook events.
- Implemented `ingest_episode_step.py` for validating and enqueuing episode payloads via a POST request.
- Developed `query_graph_step.py` for performing semantic searches in the Graphiti Knowledge-Graph.
- Introduced an `__init__.py` file for the graphiti steps module.
