Pass file path of each doc reference in references returned by API

- Pass file path of reference along with the compiled reference in
  list of references returned by chat API converts
- Update the structure of references from list of strings to list of
  dictionary (containing 'compiled' and 'file' keys)
- Pull out the compiled reference from the new references data struct
  wherever it was is being used

src/khoj/processor/conversation/openai/gpt.py

@@ -127,7 +127,7 @@ def converse(
     """
     # Initialize Variables
     current_date = datetime.now().strftime("%Y-%m-%d")
-    compiled_references = "\n\n".join({f"# {item}" for item in references})
+    compiled_references = "\n\n".join({f"# {item['compiled']}" for item in references})
 
     conversation_primer = prompts.query_prompt.format(query=user_query)