[Enhancement] Support CSS values for defaultSize, maxSize & minSize

[11xdeveloper]

The Panel component should be able to take CSS values for defaultSize, maxSize & minSize

e.g.

// ...
<Panel
    defaultSize='10svw'
    {/* ... */}
>
// ...

Much more convenient not having to use window.innerWidth / window.innerHeight.

As well as more accurate when it comes to newer values such as dvw, dvh, swv, svh, etc.

[bvaughn]

Panel size constraints are exclusively percentages. No CSS unites– pixel or otherwise– are supported.

The FAQ mentions this:

Can panel sizes be specified in pixels?

No. Pixel-based constraints added significant complexity to the initialization and validation logic and so I've decided not to support them. You may be able to implement a version of this yourself following a pattern like this but it is not officially supported by this library.