Autorelease

We want to automate more things when a new release is published. These changes will publish a news item about the new release and also highlight it in the daily emails.

As this is kind of annoying to test, I'm including some proof that it works. The emails look like this:

And the news item looks like this: https://codimd.web.cern.ch/Ni2sabYHRhOhlZBnL7as3w?both

The release notes should be downloaded by rhel_release_notes independently, so they should be available by the time the daily snapshotting script runs and publishes the news item. Hopefully.