Add question caching

### Description

Add a question caching feature. Pseudocode based on other repo-

```
def chat_completion(user_input):
# Generate embeddings from the user input
user_embeddings = generate_embeddings(openai_client, user_input)
# Query the chat history cache first to see if this question has been asked before
cache_results = cache_search(vectors=user_embeddings , num_results=1)

if len(cache_results) > 0:
return cache_results[0]['completion'], True
else:
# Perform vector search
search_results = get_similar_docs(openai_client, dbsource, user_input, 3)
print("Getting Chat History\n")
# Chat history
chat_history = get_chat_history(1)

# Generate the completion
print("Generating completions \n")
completions_results = generatecompletionede(user_input, search_results, chat_history)

# Cache the response
cacheresponse(user_input, user_embeddings, completions_results)

print("\n")
# Return the generated LLM completion
return completions_results['choices'][0]['message']['content'], False
```