For envoy/#1411
Adding it in a structured proto because in the long run I anticipate us wanting to have per-cluster port ranges we bind to and it makes sense to me if we're going to eventually allow the bootstrap and cluster config to interact that we stick all the interacting bits in another message.
This patch adds a static bootstrap proto that is expected to be provided
on the filesystem or command-line. This should enable Envoy to then
either fetch the rest of config from disk or reach out to the various
management servers for the rest of the APIs.
Fixes#93.
alyssawilk
Piotr Sikora
htuch