Removing Kickstart-specific elements from the Shiny. These are being moved to an admin subtheme for Kickstart.

Issue #1856618 by hstrindb: fixing margin issue with configuration page when descriptions are hidden

Issue #1841052 by Zach Harkey: Fixing disabled checkboxes in tables, moving some styles from contrib to default stylesheet

Issue #1806834 by MDJ Webdiensten: applying fixes for non-kickstart collapsible filters, bulk operations alignment, and admin menu bug

Removing styles that have been moved to Commerce Back Office and using a more generic .commerce-backoffice-view class for many styles

Issue #1824076 by jsacksick: Fixing the Firefox-specific positioning issue with ctool buttons in tables

Issue #1820900 by GuGuss: Fixing overlap issues with add comment form, also fixing some discrepancies in the comment form when expanded