docs migration: Container Lifecycle Hooks into Concepts (#2564)

* initial commit for structure

* migrate Container Lifecycle Hooks and related files to Concepts

* update Concepts ToC

* fix formatting

* Formatting tweaks

* comment out What's next

* remove What's next

* Begin rewrite of container-lifecycle-hooks.md

* incremental update to edit

* Split Container Lifecycle Hooks into container-lifecycle-hooks.md and container-environment.md; change all referring links.

* Add concept template to volumes.md and images.md

* Apply changes for steveperry-53 feedback.

* fix format issue

* tweak formatting

* fix Concepts ToC

* update links

* add back changes to Concepts ToC

* fix a link

* update links

docs/concepts/containers/images.md

@@ -5,15 +5,17 @@ assignees:
 title: Images
 ---
 
-Each container in a pod has its own image.  Currently, the only type of image supported is a [Docker Image](https://docs.docker.com/engine/tutorials/dockerimages/).
+{% capture overview %}
 
 You create your Docker image and push it to a registry before referring to it in a Kubernetes pod.
 
 The `image` property of a container supports the same syntax as the `docker` command does, including private registries and tags.
 
-* TOC
+{% endcapture %}
+
 {:toc}
 
+{% capture body %}
 
 ## Updating Images
 
@@ -318,3 +320,7 @@ common use cases and suggested solutions.
    - run a private registry with authorization required.
    - generate registry credential for each tenant, put into secret, and populate secret to each tenant namespace.
    - tenant adds that secret to imagePullSecrets of each namespace.
+
+{% endcapture %}
+
+{% include templates/concept.md %}