Introduce "GridView", an updated version of "ConsoleTableView"

Summary:
Ref T13546. In a future change, I'm providing a fancier version of "arc branches" that requires more sophisticated table rendering.

Implement a new view which can do some fancier things, like handle alignment of multi-line table cells.

Test Plan: See future changes.

Maniphest Tasks: T13546

Differential Revision: https://secure.phabricator.com/D21360