Horizontal Bar Plots

**What's your use case?**

Often Bar Plots have categories that are names. They are difficult to render along the _x_ axis, but will fit well along the _y_ axis (see attached chart from Excel).


**What's your proposed solution?**

It should be possible to add a checkbox to the Bar Plot to render the bars horizontally.

**Are there any alternative solutions?**

Start by locating the Bar Plot widget and its rendering entry point in the Orange3 source, then inspect how its existing plot options are exposed. The issue's requested outcome is a checkbox that renders bars horizontally, including category names along the y axis; confirm the relevant widget behavior and tests before beginning.

Written by the indexing model from the issue text.