Makes the project pane look nicer.

This has still a few missing things, but this enough to start getting
some feedback. Missing are non qt projects, a solution for the
runconfiguration, a missing black line between the treeview on top and
the project settings at the bottom. Some flickering with removing/adding
widgets to the QScrollArea and not showing the expanded widget if the
Details button is right at the bottom.

Doesn't do anything else than showing the tool chains yet.

Details:  - Seems that we use colons in forms.

Task:     235982