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* Update links to outdated user-guide and admin docs

* Add script for updating outdated links.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/policy/container-capabilities.md

@@ -88,9 +88,9 @@ spec:
 
 {% capture whatsnext %}
 
-* [Security Context](/docs/user-guide/security-context/)
+* [Security Context](/docs/concepts/policy/security-context/)
 
-* [Pod Security Policy](/docs/user-guide/pod-security-policy/)
+* [Pod Security Policy](/docs/concepts/policy/pod-security-policy/)
 
 * [SecurityContext](/docs/resources-reference/v1.6/#securitycontext-v1-core)
 

docs/concepts/policy/resource-quotas.md

@@ -26,7 +26,7 @@ Resource quotas work like this:
 - If quota is enabled in a namespace for compute resources like `cpu` and `memory`, users must specify
   requests or limits for those values; otherwise, the quota system may reject pod creation.  Hint: Use
   the LimitRange admission controller to force defaults for pods that make no compute resource requirements.
-  See the [walkthrough](/docs/admin/resourcequota/walkthrough/) for an example to avoid this problem.
+  See the [walkthrough](/docs/tasks/configure-pod-container/apply-resource-quota-limit/) for an example to avoid this problem.
 
 Examples of policies that could be created using namespaces and quotas are:
 
@@ -233,7 +233,7 @@ restrictions around nodes: pods from several namespaces may run on the same node
 
 ## Example
 
-See a [detailed example for how to use resource quota](/docs/admin/resourcequota/walkthrough/).
+See a [detailed example for how to use resource quota](/docs/tasks/configure-pod-container/apply-resource-quota-limit/).
 
 ## Read More