Add example for ServiceWorker reload on next user navigation

[stereobooster]

Complicated story. There is this practice with ServiceWorkers to show toast if new content is available and suggest user to reload browser. I see simpler solution here, instead of showing this message simply reload browser on next navigation. I suppose it is easy to do custom link component, which will render simple <Link> by default and in case of new content in SW it will render <a>, which will trigger reload in browser when clicked. WDYT?

[timdorr]

A PR would be better to discuss this.