Display services in linkerd admin dashboard

[adleong]

The current admin dashboard shows a list of clients with traffic volume and success rate for each but no mention of services.

It would be cool to have a visualization of all services (using the /rt//service metrics) and all clients (using the /rt//client metrics) as well as the traffic flow between them (using the /rt//client//service metrics).

/svc/foo ----------100rps--------> /#/io.l5d.k8s/default/http/foo
/svc/bar ----------20rps---------> /#/io.l5d.k8s/default/http/bar
/svc/bas ----------5rps----------> /#/io.l5d.k8s/default/http/bas-v1
         \
           --------95rps---------> /#/io.l5d.k8s/default/http/bas-v2