Add documentation for podpreset opt-out annotation

This adds the annotation for having the podpreset admission controller
to skip (opt-out) manipulating the pod spec.

Also, the annotation format for what presets have acted on a pod has
been modified to add a prefix of "podpreset-". The new naming makes it such
that there is no chance of collision with the newly introduced opt-out
annotation (or future ones yet to be added).

Opt-out annotation PR:
kubernetes/kubernetes#44965

docs/tasks/inject-data-application/podpreset.md

@@ -51,7 +51,7 @@ Kubernetes modifies the Pod Spec.
 
 Kubernetes annotates the resulting modified pod spec to show that it was
 modified by a `PodPreset`. The annotation is of the form
-`podpreset.admission.kubernetes.io/<pod-preset name>": "<resource version>"`.
+`podpreset.admission.kubernetes.io/podpreset-<pod-preset name>": "<resource version>"`.
 
 
 ## Enabling Pod Preset
@@ -63,6 +63,12 @@ following
 1.  You have enabled the admission controller `PodPreset`
 1.  You have defined your pod presets
 
+## Disabling Pod Preset for a pod
+
+There may be instances where you wish for a pod to not be altered by any pod
+preset mutations. For these events, one can add an annotation in the pod spec
+of the form: `podpreset.admission.kubernetes.io/PodPresetOptOut: "true"`.
+
 ## Creating a Pod Preset
 
 ### Simple Pod Spec Example