Show computed CSS info for elements

[crcn]

This is particularly important to make sure that UI is aligned with Figma. This would just be a simple panel (like chrome inspector) that shows computed CSS properties of a selected element.

[crcn]

This is actually a really good starting point for UI tooling since we should be able to edit properties directly within the computed CSS info. In addition to that, we can also include special UI controls depending on the CSS property such as color pickers, draggers (for PX measurements), etc.

After the computed style view, I think the next logical step would be to start working on canvas controls such as box model draggers, grid controls, etc.