[Feature request]: ability to theme scrollbar

[bigopon]

At the moment, there's no way to theme a scrollbar when using ux. It would be great if we could have a built-in way to unify styling scrollbar for all supported browser, mainly Firefox & webkit based browser.

Relevant links
For Firefox: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Scrollbars
For others: https://developer.mozilla.org/en-US/docs/Web/CSS/::-webkit-scrollbar

[bigopon]

@ben-girardet @serifine @EisenbergEffect

[ben-girardet]

You mean styling them for the whole application at once or on a per-component basis ?

[bigopon]

@ben-girardet we probably don't want to style the entire application, but want to have some basic utility to style scrollbar, like a CSS class named .ux-scrollbar and some theme variables. So our components and user application can share the same scrollbar styling