Add widget to HorizontalLine instead of ui.Image

[large]

Is your feature request relasted to a problem? Please describe.
HorizontalLine seems "rough" and uses ui.Image and not widget-Image to present a picture.
This implementation makes it impossible to place and manipulate where to show. It just pops up where-ever you put it to.
I have not tested with SVG, but that is not usable in my case.

Describe the solution you'd like
Making HorizontalLine show a widget would make it so much easier to show extra on a ExtraLinesData array.

Describe alternatives you've considered
If fl_chart is bound to ui.Image, consider making a wrapper class ui.Image that could contain x,y,cx,cy variables to make it possible to place in the paint-canvas.

Additional context
There is already an "suggestion" near this here: #1614