Add prometheus container level metrics

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

vendor/github.com/crosbymichael/cgroups/state.go

@@ -0,0 +1,12 @@
+package cgroups
+
+// State is a type that represents the state of the current cgroup
+type State string
+
+const (
+	Unknown  State = ""
+	Thawed   State = "thawed"
+	Frozen   State = "frozen"
+	Freezing State = "freezing"
+	Deleted  State = "deleted"
+)