Update to use @sentry/browser, remove raven-js

[amytych]

No description provided.

[timneutkens]

Thanks!

[kachkaev]

I'm curious if Sentry is something that we should import and initialize in a special way instead of making it a part of the common webpack bundle.

I once had a Next.js app that was silently crashing on the client side in a small proportion of old Android devices – that happened because Intl was not polyfiled. Finding the bug was only possible because I had the google analytics script, which was configured to send a custom event on window.onerror. The users just saw static server-rendered web pages because the entire webpack-generated JS file failed. Should Sentry be something that's fetched from CDN like in good old days?