Add correct GV for PodSecurityPolicy describer

[KnVerey]

What type of PR is this?

/kind bug
/kind cleanup

What this PR does / why we need it:

• Adds the current GroupVersion for PodSecurityPolicy to the describer lookup map. PodSecurityPolicy was removed from extensions/v1beta1 in 1.16. PodSecurityPolicy was deprecated in 1.21, but it will be supported until 1.25 and this fix is trivial.
• Removes references to kinds in extensionsv1beta1 that were removed from that group in 1.16. All the describers were already accessing via the appropriate newer GVs. If I remember kubectl's skew policy correctly, these could have been removed as early as 1.19.

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Restore kind-specific output for `kubectl describe podsecuritypolicy`

/cc @pwittrock

[k8s-ci-robot]

@KnVerey: This issue is currently awaiting triage.

If a SIG or subproject determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

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[KnVerey]

Built on master:

· kubectl describe podsecuritypolicy
Name:         example
Namespace:
Labels:       <none>
Annotations:  <none>
API Version:  policy/v1beta1
Kind:         PodSecurityPolicy
Metadata:
  Creation Timestamp:  2021-04-20T00:03:41Z
  Managed Fields:
    API Version:  policy/v1beta1
    Fields Type:  FieldsV1
    fieldsV1:
      f:spec:
        f:allowPrivilegeEscalation:
        f:fsGroup:
          f:rule:
        f:runAsUser:
          f:rule:
        f:seLinux:
          f:rule:
        f:supplementalGroups:
          f:rule:
    Manager:         kubectl
    Operation:       Update
    Time:            2021-04-20T00:03:41Z
  Resource Version:  37460
  Self Link:         /apis/policy/v1beta1/podsecuritypolicies/example
  UID:               97a541d9-83bf-4777-b0f2-a5caddcf874e
Spec:
  Allow Privilege Escalation:  true
  Fs Group:
    Rule:  RunAsAny
  Run As User:
    Rule:  RunAsAny
  Se Linux:
    Rule:  RunAsAny
  Supplemental Groups:
    Rule:  RunAsAny
Events:    <none>

Built on this branch:

· kubectl describe podsecuritypolicy
Name:  example

Settings:
  Allow Privileged:                       false
  Allow Privilege Escalation:             true
  Default Add Capabilities:               <none>
  Required Drop Capabilities:             <none>
  Allowed Capabilities:                   <none>
  Allowed Volume Types:                   <none>
  Allow Host Network:                     false
  Allow Host Ports:                       <none>
  Allow Host PID:                         false
  Allow Host IPC:                         false
  Read Only Root Filesystem:              false
  SELinux Context Strategy: RunAsAny
    User:                                 <none>
    Role:                                 <none>
    Type:                                 <none>
    Level:                                <none>
  Run As User Strategy: RunAsAny
    Ranges:                               <none>
  FSGroup Strategy: RunAsAny
    Ranges:                               <none>
  Supplemental Groups Strategy: RunAsAny
    Ranges:                               <none>

[KnVerey]

/test pull-kubernetes-e2e-kind

[pwittrock]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: KnVerey, pwittrock

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/kubectl/OWNERS [pwittrock]

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[KnVerey]

/test pull-kubernetes-e2e-gce-100-performance