Update User Guide and Admin links to point to new resources. (#3438)

* Update links to outdated user-guide and admin docs

* Add script for updating outdated links.

* Update regex to include init-containers file.

* Pull upstream, rewrite links in and to namespaces walkthrough.

docs/concepts/workloads/controllers/replicaset.md

@@ -13,7 +13,7 @@ title: Replica Sets
 
 ReplicaSet is the next-generation Replication Controller. The only difference
 between a _ReplicaSet_ and a
-[_Replication Controller_](/docs/user-guide/replication-controller/) right now is
+[_Replication Controller_](/docs/concepts/workloads/controllers/replicationcontroller/) right now is
 the selector support. ReplicaSet supports the new set-based selector requirements
 as described in the [labels user guide](/docs/user-guide/labels/#label-selectors)
 whereas a Replication Controller only supports equality-based selector requirements.
@@ -28,7 +28,7 @@ imperative whereas Deployments are declarative, so we recommend using Deployment
 through the [`rollout`](/docs/user-guide/kubectl/v1.6/#rollout) command.
 
 While ReplicaSets can be used independently, today it's mainly used by
-[Deployments](/docs/user-guide/deployments/) as a mechanism to orchestrate pod
+[Deployments](/docs/concepts/workloads/controllers/deployment/) as a mechanism to orchestrate pod
 creation, deletion and updates. When you use Deployments you don't have to worry
 about managing the ReplicaSets that they create. Deployments own and manage
 their ReplicaSets.
@@ -79,7 +79,7 @@ frontend-qhloh   1/1       Running   0          1m
 ## ReplicaSet as an Horizontal Pod Autoscaler target
 
 A ReplicaSet can also be a target for
-[Horizontal Pod Autoscalers (HPA)](/docs/user-guide/horizontal-pod-autoscaling/),
+[Horizontal Pod Autoscalers (HPA)](/docs/tasks/run-application/horizontal-pod-autoscale/),
 i.e. a ReplicaSet can be auto-scaled by an HPA. Here is an example HPA targeting
 the ReplicaSet we created in the previous example.