Add statefulsets to the dashboard and CLI

[ihcsim]

This PR adds statefulset resources to the dashboard, CLI and grafana. Note that at present, no TCP metrics will appear. See #2223 and #2224.

The screenshots below show test results with redis and nginx, used to demonstrate http and tcp traffic metrics.

$ bin/linkerd tap statefulset --namespace default
req id=6:1 proxy=in  src=172.17.0.17:58894 dst=172.17.0.15:80 tls=true :method=GET :authority=nginx.default :path=/
rsp id=6:1 proxy=in  src=172.17.0.17:58894 dst=172.17.0.15:80 tls=true :status=200 latency=3054µs
end id=6:1 proxy=in  src=172.17.0.17:58894 dst=172.17.0.15:80 tls=true duration=33µs response-length=14B

$ bin/linkerd top statefulset --namespace default
(press q to quit)

Source  Destination  Method      Path   Count    Best   Worst    Last  Success Rate
curl    nginx-0      GET         /         28   435µs     5ms     5ms       100.00%
curl    nginx-2      GET         /          7   510µs     5ms     5ms       100.00%
curl    nginx-2      GET         /         14   487µs     5ms     2ms       100.00%

Fixes #1983

Signed-off-by: Ivan Sim ivan@buoyant.io

[siggy]

awesome! mostly cosmetic comments around statefulset -> sts, and sorting resource types.

we are not great about sorting our k8s resource types, but as the number of types grows, i think it becomes more important. not every code path uses exactly the same set of resources, so sort order helps in identifying differences. i noted a few particular sorting locations in the code review, but not all of them. with that in mind, a few guiding principles:

• if a list of resources is already sorted, keep it sorted
• if you encounter code where sorting is not correct, feel empowered to clean it up
• there may be exceptions for UI/doc purposes. the stat help output sorts some exceptional resources at the bottom, but all things being equal, i'd recommend resorting the first 6 items together, then sort the 3 exceptional types together, and then all at the bottom.

  Valid resource types include:
  * daemonsets
  * deployments
  * namespaces
  * pods
  * replicationcontrollers
  * statefulsets
  * authorities (not supported in --from)
  * jobs (only supported as a --from or --to)
  * services (only supported if a --from is also specified, or as a --to)
  * all (all resource types, not supported in --from or --to)

[rmars]

🚀 nice!!!

[siggy]

Awesome! 🚢 👍