Overhaul print CSS styles and better integrate with Vanilla core

## Component/pattern to amend

Presently, the print CSS styles for various sites tend to live in their own file:

https://github.com/canonical/ubuntu.com/blob/main/static/sass/print.scss

These print.css files also often live separately from core site styles, resulting in an extra network request to retrieve them.

There's probably an opportunity here to create some print styles as part of Vanilla core, so these don't need to be created uniquely for each site. We'll need to do some analysis to determine what various sites are doing with their print styles and which parts of these print styles could be upstreamed into new Vanilla core print styles.

Start by reviewing the existing print styles in static/sass/print.scss from ubuntu.com, then compare print CSS patterns across the sites mentioned in the issue. Identify which styles can be upstreamed into Vanilla core, integrate the shared print styles there, and verify that sites no longer need separate print stylesheets or an extra request.

Written by the indexing model from the issue text.