Mobile column view redux

[andyra]

A few changes to how the column view works:

• Global layout change that uses grid containers in an effort to better manage places where we need full-viewport-height scrolling.
• Each card column is now individually scrollable
• Collapsed columns now only look collapsed on larger viewports (e.g. columns expanded by default on small viewports)
• On small viewports, you can now swipe left/right between columns.

Since this touches the application layout, trays, and the main column layout, I want to get this on beta first so we can put it through the paces. Most likely problems I can see cropping up are unexpected scroll containers.