Merge user and question microservices

[iynixil]

note: this merging of services is built upon user-service branch

fetch this PR changes onto local repo: (since its not pushed into the merge-user-question branch yet)
git fetch upstream pull/33/head:<branch name>
git checkout <branch name>
this creates a new branch in your local repo with the <branch name> to view this PR's changes

Changes:

change file structure of backend/:

• every microservice in its own directory
• every microservice has controller and routes folders
• common files used across services are left in backend/ e.g firebase.js
• changed command to run backend server: in backend/package.json, npm start was node index.js, now npm start is nodemon index.js
  • this allows changes to be reflected instantly when file is changed without restarting backend server

change file structure of frontend/:

• renamed frontend folder from my-app/ -> frontend/
• put all pages under frontend/src/pages/, pages separated by microservice
• each microservice page directory has styles and utils folder
  • styles for .css files, utils for storing utility functions (can delete utils at the end of project before submission if not used)
• put common components used across all pages under frontend/src/components
  • components has styles folder for .css files

general:

• added a comment at the top of every file, Author(s): to include names of people who created most of the functionality used in the file. makes it easier to write individual contribution later on
• the app looks different because the .css files are conflicting with each other

if there are issues with functionality/etc, can let me know

[xuelinglow]

tested and lgtm

[whitesnowx]

Looks good to me and works fine on correct use

I think this could fall under n2h securities concern, but not sure whether you want to fix this in this milestone:

Injection using /" crashed the backend