Revise Pod concept (#22603)

* Revise Pod concept

Adapt the existing Pod documentation to suit the Docsy theme, by
promoting the Pod concept itself to /docs/concepts/workloads/pods/

Following on from this, update the Pod Lifecycle page to cover the
lifecycle of a Pod and follow on directly from the Pod concept,
for readers keen to understand things in detail.

This change also removes the automatic contents list from the Pod
overview page. Instead, the new page links to all the pages
inside the Pod section.

* Update links to Pod concept

Link to updated content

* Incorporate Pod concept suggestions

Co-authored-by: Celeste Horgan <celeste@cncf.io>

* Revise StatefulSet suggestion for Pod concept

Co-authored-by: Celeste Horgan <celeste@cncf.io>

Co-authored-by: Celeste Horgan <celeste@cncf.io>

content/en/docs/concepts/configuration/pod-priority-preemption.md

@@ -255,7 +255,7 @@ makes Pod P eligible to preempt Pods on another Node.
 #### Graceful termination of preemption victims
 
 When Pods are preempted, the victims get their
-[graceful termination period](/docs/concepts/workloads/pods/pod/#termination-of-pods).
+[graceful termination period](/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination).
 They have that much time to finish their work and exit. If they don't, they are
 killed. This graceful termination period creates a time gap between the point
 that the scheduler preempts Pods and the time when the pending Pod (P) can be
@@ -268,7 +268,7 @@ priority Pods to zero or a small number.
 
 #### PodDisruptionBudget is supported, but not guaranteed
 
-A [Pod Disruption Budget (PDB)](/docs/concepts/workloads/pods/disruptions/)
+A [PodDisruptionBudget](/docs/concepts/workloads/pods/disruptions/) (PDB)
 allows application owners to limit the number of Pods of a replicated application
 that are down simultaneously from voluntary disruptions. Kubernetes supports
 PDB when preempting Pods, but respecting PDB is best effort. The scheduler tries