PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful

vendor/github.com/prometheus/procfs/README.md

@@ -0,0 +1,10 @@
+# procfs
+
+This procfs package provides functions to retrieve system, kernel and process
+metrics from the pseudo-filesystem proc.
+
+*WARNING*: This package is a work in progress. Its API may still break in
+backwards-incompatible ways without warnings. Use it at your own risk.
+
+[![GoDoc](https://godoc.org/github.com/prometheus/procfs?status.png)](https://godoc.org/github.com/prometheus/procfs)
+[![Build Status](https://travis-ci.org/prometheus/procfs.svg?branch=master)](https://travis-ci.org/prometheus/procfs)