Support javafx.web on all platforms

[maxum2610]

Build the static lib for javafx webkit for each platform. Include the javafx webkit jar in Substrate, and link the static libs in the executable.

[mipastgt]

But I hope you only do that when needed. The executable is already big enough :-)

[jperedadnr]

So far, only Windows lacks support for WebView: https://docs.gluonhq.com/#_platforms

[credmond]

Hey -- any plans (or link to see the progress) of the WebView Windows support?

I see this question getting repeatedly asked in different places and the response usually includes a link to https://docs.gluonhq.com/#_platforms to show it's not supported, but there's no indication of when WebView Windows support is coming (or what the problem with it is...)...?