add glossary term for pod security policy

_data/glossary/pod-security-policy.yaml

@@ -0,0 +1,16 @@
+id: pod-security-policy
+name: Pod
+full-link: /docs/concepts/policy/pod-security-policy/
+related:
+- container
+- sidecar
+- deployment
+- statefulset
+- security
+tags:
+- core-object
+- fundamental
+short-description: >
+  Pod Security Policies enable fine-grained authorization of {% glossary_tooltip term_id="pod" %} creation and updates.
+long-description: >
+  A Pod Security Policy is a cluster-level resource that controls security sensitive aspects of the Pod specification. The `PodSecurityPolicy` objects define a set of conditions that a Pod must run with in order to be accepted into the system, as well as defaults for the related fields. Pod Security Policy control is implemented as an optional admission controller.