Upgrading to Angular 12 and NgBootstrap 10

[softsimon]

Let's test so nothing got broken on the site due to this upgrade.
NgBootstrap had to be upgraded to fit with Angular 12 and make sure that nothing broke using these components. (Typeahead, accordion)

[wiz]

Apparently there was an option in Angular 11.1 that is now enabled by default in Angular 12 called "Critical CSS inlining" which causes CSS to be loaded asynchronously, so the initial page renders faster now, but looks really weird until a split second later when the CSS loads. To resolve this we need to configure the "Critical CSS inlining" using a webpack plugin. More information on these blog articles:

https://blog.ninja-squad.com/2021/05/12/angular-cli-12.0/
https://blog.ninja-squad.com/2021/01/21/angular-cli-11.1/

[wiz]

Tested ACK @ bbee2dc

Disabled the inlineCritical for now, will implement support for this in a separate PR later following the example in https://dzone.com/articles/critical-css-and-webpack-automatically-minimize-re