Fix the following issue:
Operator-managed Pods rejected under the Restricted Pod Security Standard
We're rolling postgres-operator out into a cluster where namespaces enforce the
Kubernetes Restricted Pod Security Standard. When the operator brings up
its Postgres pods in such a namespace, the API server rejects them (or, with
warn/audit configured, surfaces a warning for every container) because the
containers' SecurityContext does not satisfy the Restricted profile.
Looking at RestrictedSecurityContext() in internal/initialize/security.go,
most of what Restricted requires is already there — runAsNonRoot, dropped
capabilities, no privilege escalation, read-only root filesystem, etc. — but
the resulting pods still trip the Restricted check, so the defaults aren't
quite "Restricted-compliant" out of the box.
For an operator that's clearly trying to ship a hardened SecurityContext
(RestrictedSecurityContext is even the function name), it would be great
if pods produced by it could be deployed into a Restricted-enforcing namespace
without the user having to layer extra mutating webhooks or post-process the
generated specs.