* Write BUILD_ID when building.
It's a random id (uuid.v4())
* Add buildId to the core JS files.
* Add immutable cache-control header.
Only if the buildId is matched.
* Set '-' as the dev buildId always.
* Add buildId handling for JSON pages.
* Remove the use of CDN and bundle everything inside the app.
We still pre-build the prefetcher because it needs
different webpack config which only targets browsers
supports Service Workers.
* Remove cdn config item.
We no longer using it.
* Stop adding script tags when staticMarkup=true
* Remove babel-plugin-transform-remove-strict-mode NPM module.