Make it easy to use Lets-Plot with Panel

Hi Lets-Plot

A user of [Panel](https://panel.holoviz.org/) is asking how he can use `Lets-Plot` with Panel to build data apps in https://github.com/holoviz/panel/issues/5475

I've investigated and found a quick, preliminary solution in https://github.com/holoviz/panel/issues/5475#issuecomment-1704336379

Based on that, it would be really nice if the Lets-Plot javascript provided

- A way to set responsive (100%) height and width instead of specific height and width doubles.
- An official way to clear or update the plot. Right now I just use `.innerHTML=""` on the parent div.

If you are interested in getting `Lets-Plot` supported with Panel and the combo documented in the `Lets-Plot` docs, then please reach out in the original Panel issue. Thanks.

https://github.com/JetBrains/lets-plot/assets/42288570/b3f9d3c0-2b47-4292-b782-8d3598ae32d9