Add Service Workers and PWA for Offline support

[abderrahmaneMustapha]

When there is no internet connection the user can not access the articles or the learn section

we can use a service worker and progressive web apps to add offline support and make your web app installable like native apps

[ZibanPirate]

yes, a very welcomed feature, i'm planning to add it once the website is stable, otherwise the caching will cause serious problem later, @abderrahmaneMustapha you can try implementing it, will test it on staging first.