color: Modernize the panel a bit
- Use AdwPreferencesPage/AdwPreferencesGroup. The panel looks like before, but with with less .ui code
- Use AdwStatusPage when there are no devices that can be color managed:
Previously, the panel would just show a plain "Unable to detect any devices that can be color managed" label with nothing else
Closes #2421 (closed)
Edited by Automeris naranja