Added tool to get boostraping url from an NSG

[maesoser]

Added a simple tool to get the Activation URL from an NSG in order to boostrap it.

I think it could serve as an useful example cause it shows a way for capturing events using Bambou PushCenter. Code maybe need some refactorization, let me know what do you think!

Sergio.

[hellt]

Hey Sergio, thanks for you contribution. A slight issue with the push center is that in my trials it was not 100% reliable. I mean that sometimes there was no activation url available in the push center feed, and the issue was with some 5.x releases.

@pdellaert might have a better view on the push center as a feature, but I heard that one should not rely on it (at least in production).

On the other hand, if you are familiar (or want to get familiar) with AMQP or JMS buses, you can try to implement/use AMQP listener in Go and fetch the events (like an NSG notification) from there. These buses are 100% reliable and the community would be grateful to have some Go code interacting with AMQP for instance.