Add support for terain

[fnikolai]

Currently, Frisbee supports "deployment scenarios", where the user must statically define the various properties (e.g, networks distances, failure rates, etc etc).

A more elaborate way would be to describe a "terain" that represent the physical infrastructure, and that terain define the properties. For example, the terain would account the "mobility" of a service and will accordingly modify the network rules to capture for propagation delays.