Support separate fonts for palette entry and container

[ptziegler]

The palette only allows the user to set a single font, which is used for all figures.
I think it would be useful if one set different fonts for categories and entries, in order to e.g. emphasize one over the other.
A simple use case would be to make the categories bold.

[ptziegler]

Suggestion:

Split up the Palette Font key in the PaletteViewerPreferences into Entry Font and Category Font.

For backwards compatibility, setFontData() would update the entry and category font, but it would also be possible to configure either one via dedicated methods.

[github-actions]

This issue is stale because it has been open for 90 days with no activity.