Resolve "Frontend - Platform - Look into using `.pug` for the templates"

@2955053f Okay this ended up being a pain, I attempted to simply swap over the build/serve builders (see angular.json) to the package listed in the issue, the issue with that is that it's got conflicting peer deps, I believe it's to do with the version of angular it requires, this makes it really annoying to add new deps in (and any time you want to npm install you will need to specify either --force or --legacy-peer-deps).

I then implemented my own builder (remind me to never attempt to do that again), finally looked into how ngx-pug-loader has been created and then realised we could cut out a lot of their waffle with Angular versions and just directly use the two custom webpack loaders they use.

To Test

• cd to frontend
• npm ci npm run start
• you should see the new Hello World screen
• play about with the template from here
• try adding in extra divs
• try adding in a class (you will need to add back the style sheet or add to styles.scss)

Please don't push any test change any code, just test locally pls.

Closes #13 (closed)