Feat/gateway selector minimal

Some refactoring on top of the previous mr. Doing fallback for gateway selection, per city, if menshen not usable. I have been playing a bit with qml quick controls, exploring the use of tabs.

Please do note that the systray menu is still a work in progress, we should see to simplify it and moving some of the items to a menu bar in the main window.

TODO

• should pass other gws for the same location.