feat(router): Add PROXY protocol support

PROXY Protocol support is very useful for scenarios where you have
to run a load balancer in front of the deis-routers in TCP mode instead of
HTTP mode.

In TCP mode you usually do not get access to the external IP address. However,
if the load balancer, like Amazon ELB or HAProxy support the Proxy protocol,
then the protocol will provide the remote connecting address.

if `/deis/router/proxyProtocol` exists, we will listen for the proxy_protocol on
port 80. Any normal HTTP requests to this port will get a 400/413 HTTP Error.
feat(router): Move PROXY protocol to 8080

The commit exposes port 8080 where, if `/deis/router/proxyProtocol` exists will
listen to port 8080 with Proxy Protocol enabled. This allows normal HTTP traffic
over port 80 (for instance for /health-check).
docs(router): Add PROXY protocol configuration docs