Add "Tile" actions and shortcuts to window menu

Related to #1028

## Problem

It's not obvious from the window menu that you can tile windows left/right. We show it in the Keyboard Shortcuts overlay, but not contextually in the window menu, where it might be more obvious and connected to other window actions.

## Proposal

Add a "Tile window left" and "Tile window right" actions to the window menu. This should probably also include a more general cleanup/reorganizing and grouping of window menu actions since there's a lot going on in there.

## Prior Art

macOS has a sort of context menu on their maximize button with tiling options:


Chrome OS has a weird [click-and-hold on the maximize button](https://support.google.com/chromebook/answer/177891?hl=en) that then shows a left and right arrow for tiling.

It is [not clear if Windows has a context menu](https://support.microsoft.com/en-us/windows/snap-your-windows-885a9b1e-a983-a3b1-16cd-c531795e6241) for this, but they support dragging windows and keyboard shortcuts.

Android has a "Split screen" action in the window menu which automatically tiles it to the top or left of the screen, then lets you choose another app to fill the other space.