Improved tab and directional navigation

[miroiu]

📝 Description of the Change

• Automatically bring item containers into view when navigating to them via keyboard if they are not already in view
• Enable directional navigation for item containers within the editor

Closes #194

🐛 Possible Drawbacks

None.

[Nintynuts]

It's great you're improving this, so thanks.

For me in the current version, with the focus rect style overridden (as you have in this review) it results in a connection-shaped rectange appearing when trying to tab navigate (it tabs through all the connections before the nodes), but all the rects are anchored to 0,0 on the canvas rather than around the connection. This seems to be because they're added to a canvas, but their left and top properties are not set. I'm guessing that ConnectionContainer overrides Focusable to true because the connections are shapes and aren't focusable themselves? Maybe if the container could know the top left position of the shape and the shape was anchored so its bounds line up with 0,0 in its local coordinate space it would work? If not maybe the focus rect should just be disabled for them and change the connection drawing to indicate focus instead.

Do you still see those issues with these changes?