[Backend] Create a shared library for the backend services

[kylestang]

Description

Adds a backend/lib folder with a js package and associated docker config

Closes #149

How to Test

docker compose up --build

curl localhost:8213/api/review

Should print Hello World! to the server console.

Checklist

• [x] The code includes tests if relevant
• [x] I have actually self-reviewed my changes and done QA