Make topology zoomable

[DorinevanderVlies]

When a multinode topology is used often only part of it is displayed in the interface. Both in the network tab and in the edit --> topology.
It would be nice if the interface was zoomable.

Notifying @AlexanderWirtz

[AlexanderWirtz]

Alternatively, we could provide a button that opens the topology view in a separate tab, so that the whole screen can be used to view a topology. This screen is available when you open a topology in the top-level menu item Topologies.

We could also make the field of view size customizable so that the user decides how much space to dedicate to viewing the topology.