add metadata filters to help with our results

[jackabald]

from llama_index.core.vector_stores.types import (
   MetadataFilter,
   MetadataFilters,
)

query_engine = index.as_query_engine(
   filters=MetadataFilters(
      filters=[
         MetadataFilter(key="book", value="paul_graham", operator="!="),
      ]
   ),
   similarity_top_k=2,
)
response = query_engine.query("What did the author learn?")
print(textwrap.fill(str(response), 100))

This is an example from these docs: https://docs.pingcap.com/tidbcloud/vector-search-integrate-with-llamaindex on how when we query for data like how response does in code_search.py we can use metadata filters. Research these filters and find if they could be helpful.