Configure the navigate button to do just that

[blackjack2693]

Depends heavily on #127
The button "Navigate" in the location overview should do what it is designed to do. If clicked the navigation from the overview of a certain location A, the navigation from my current location to A should start. Have a look at the Sigma prototype to get a better understanding of the function. The first two pictures show a mockup of the location overview from where the navigation should start and at the last one the started navigation.
It might be necessary to store coordinates to places somehow. This might benefit from collaboration with issue #182.
Most important are Hörsaalgebäude and Villa.