Scale bar styling

[aliaksandr-voranau]

Hello!

Is it possible to add functionality for styling scale bar in components (PictureInPictureViewer, SideBySideViewer, VolumeViewer) ?
For example possibility to change: color, font size, thickness of the bar.

Or maybe it will be easier just to add background to the scale bar? Because when we change options for our images and they becomes lighter, it's really hard to read the value in the scale bar.

[ilan-gold]

If you submitted a PR, we would be happy to review! Happy to guide as needed!