Add some new KDE applications

This MR packages most of the applications to be shipped in the default Plasma Mobile image, as discussed with the Plasma Mobile team on Akademy.

• Okular
• VVave
• Pix
• Index

Also included is Kube, a QML-based email client which is supposed to get a mobile UI. I'm not sure if we'll keep it, we'll have to see how it's development goes, but it's good enough for now.

Lastly I packaged Itinerary. It was shown at Akademy, and is basically a travel assistant. You can use it to board flights by using it's rendered flight ticket for example. There is some work to do with this package still, but it should be good enough for now.