add API route to run queries from clients

[mongodben]

TypeScript/Next.js server routes with endpoint to respond to natural language user queries in natural language response with accurate data from the indexed site. Format answers in Markdown with links to relevant content on the site.

• Use AI embedding API to create and query embeddings for site data. Use Atlas Search $knnBeta operator for this.
• Use LLM AI to summarize results from query.

[mongodben]

there's a basic POC here - https://github.com/mongodben/mongodb-oracle/blob/main/pre-skunk-poc/generate-index/lib/test-query.ts

for LLM summary, this script uses "text-davinci-003", which is based on OpenAI GPT-3. it works fine.

we could likely get better results using:

1. the brand new ChatGPT API (docs)
2. use GPT 3.5 instead of GPT 3 (i'm not sure how this would work offhand)

[mongodben]

more than 90% sure we can marginally improve the results quality while reducing cost 10x by using the model "gpt-3.5-turbo" with 0 other changes.

[mongodben]

resolved by https://github.com/mongodben/mongodb-oracle/pull/19