Resizing tiled windows with the keyboard

[maria-komarova]

Instead of either increasing window width or height in both directions we'd like to allow people growing or shrinking only one side of the focused window. That would make it more similar to resizing a window with the mouse. Adjacent windows and window groups located along the axis that gets adjusted should be resized accordingly.

Use Super+R+Arrow keys to increase the window size, and Shift+Super+R+Arrows to decrease the window size. Secondary option - Super+Alt+Arrows and Shift+Super+Alt+Arrows. We'd like to treat Super+R as a kind of "mode" that is toggled on on the press of the combination and is toggled off on the release of the keys.