feat(ui): create buttonbar widget for SParam enum

Description

The SParameter supports enums, though they are not simple to use, in terms of xml and ui. A new enum display will be added, corresponding to a bar, with buttons, image and text which allow to select a specific value.

It should have the features of enumSParam, with icons and labels. The unselected options are gray, while the selected one is in full color.

Gui test are added, to check this feature, and a sample is added in SParameter.

Closes #1110 (closed)

How to test it?

Run exsparameters and click on the buttons in the button bar in both tops panels.