Create support for routes

[DylanTom]

Issue
We want to maintain the filesize and scope of index.js

Task
Implement routes.js which will store all the POST, GET, PUT, DELETE routes

To-do

• Create routes.js in src
• Use online documentation to see how to use express and router
• Move the currently commented code in index.js regarding various route API calls to routes.js
• Clean up the backend and ensure the code works by clicking the button; verify it outputs the correct message

[DylanTom]

PR Done