Add bundle size to CI

[gregtatum]

It would be nice to add this to the CI, I don't really feel like checking it manually, but it would be nice to know. I was quite surprised by the js zip file size.

https://github.com/siddharthkp/bundlesize

┆Issue is synchronized with this Jira Task

[julienw]

As a note, we see the bundle size in the CI logs, at the step yarn build-prod:quiet. But this is quite not practical.