update example for vector database embeddings types

update readme and syllabus

add header footer and finish curriculumn files

update example required packages

update rag example with langchain

fix end of file issue

modify markdown alert box issue with Github display

update README for lab m03

add lab for RAG system, use new approach of repeat-then-create

update vector database md

add fun pdf text for demo

update content RAG

revise RAG content, add demo

revise content for vector database

temp add vector datbases content