Copy media library styles from Seven to Claro

Problem/Motivation

Media Library has been marked as stable in 8.8.x and as a result, most of the related styles were moved to Seven. Right now, if someone tries to use Media Library with Claro, it's unstyled for the most part which leads to poor UX.

Proposed resolution

Copy Seven Media Library styles to Claro as a starting point. Work on redesigning Media Library in follow-up issues.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet