Migrate the dashboard-level styles into generic datagrid classes.
Review Request #7223 — Created April 17, 2015 and submitted
We had a number of styles that were originally specific to the dashboard, but later became used for other pages (such as the user page). This included the full-page wrappers, sidebar, etc. These are useful classes, and pages shouldn't need to pretend to be the dashboard to get it. Those classes have now been made more generic, with "dashboad" prefixes replaced with "datagrid." This is really just code shuffling and renames. Nothing substantial has changed.
Tested that all the datagrids and their functionality still worked. This
includes all the special functionality of the dashboard (batch selection,
actions, etc.), and column editing/reordering.