Settings, replace files, sorting by size, tweaks.

Add settings to show file sizes and advanced storage devices, both
disabled by default. Add sorting by size when enabled in settings.

Always show all documents, but only allow selection when they match
MIME filter. When creating, select entire filename on focus. When
creating, treat selected documents as replacement targets using that
exact Uri unless display name is changed.

Show available bytes for device roots. Show empty text label in
empty directories. Split grid backend and details into two separate
lines. Fix path label ordering when rendering recent directories.

Change-Id: I44c62e8adb8ca7d4355510a13d1ba975196a2d29