In recent changes, much of the logic and styling specific to the

datagrid pages have been moved out into a series of new CSS and

JavaScript components. These covered page management features like the

full-page content mode, the drawer overlaying the sidebar, and the

revised sidebar support.
This change updates the datagrid pages to make use of these new

components, simplifying the code and making them consistent with any

other pages that end up using these components (such as the in-progress

administration UI rewrite).
The batch operations pane in the dashboard has been replaced by the new

drawer support, which also provides new mobile batch operation support.
The sidebar now uses the new rb-c-sidebar component styles, fixing

some visual issues in the old implementation and giving us a more

mobile-friendly sidebar.
All other functionality remains the same.

Unit tests pass.
Tested the sidebar, drawer, and basic functionality for the dashboard,

and all basic functionality for all the other current datagrid pages,

in desktop and mobile modes.