[Backend] Add GET /orders/:id endpoint

[nataliasowa]

Description

This PR provides order info to display orders by order id.

Fixes #101

How to test?

npm run db:setup npm run dev http://localhost:3000/api/orders/{id} Swagger -> http://localhost:3000/api/documentation/#/

Checklist

• [x] I have performed a self-review of my own code
• [x] I have followed the name conventions for CSS Classnames and filenames, Components names and filenames, Style filenames, if you are in doubt check the the project README.MD and here https://github.com/HackYourFuture-CPH/curriculum/blob/master/review/review-checklist.md
• [x] I have commented my code, particularly in hard-to-understand areas, if you code was simple enough mark the box anyway
• [x] I have made corresponding changes to the documentation, if you code was simple enough mark the box anyway
• [ ] This PR is ready to be merged and not breaking any other functionality

[miltonhultgren]

Could I suggest updating the PR title and the merge message to something like: [Backend] Add GET /orders/:id endpoint