Display a better Text for apps if no connection is selected

[grafst]

In the "Usage" Tab in the "current app" section: Display a better Text if no Connection is selected. See screenshot:

[ghost]

Thanks for your interest in Nutty and suggestions to improve the same. Definitely agree that the messaging can be improved with context. One of the ideas I had was to show the page with results from one of the connections and then let the user change it to a different connection, but then it would add to the screen load time, so I though it is best to show an empty page at the start.

Will add a check in all tabs and set the messaging appropriately based on whether a connection is selected or not. I think I can loose the "Results:" prefix - it has stayed on from the time I was tinkering with vala and learning to code. Looks like a developer debug message in the app now :-)