Visor may find it's own routes as fallback or on demand

[0pcom]

Due to intermittent deployment stability issues, a fall-back of local route calculation has been implemented.

A flags have been added to client apps, --local-route to calculate routes locally instead of using route finder

This entails the visor downloading transport discovery data set, and uses the existing route finder implementation run locally on the visor.

Local route calculation is automatically triggered if the route finder does not respond with routes after 3 requests.