* [AUR-362] Add In-memory vector store
* [AUR-362] fix delete fun input format
* [AUR-362] revise persist and from persist path to save and load
* [AUR-362] revise simple.py to in_memory.py
Design the base interface of vector store, and apply it to the Chroma Vector Store (wrapped around llama_index's implementation). Provide the pipelines to populate and retrieve from vector store.