Update registry template (#8198)

* Add registry replica setting

* Add registry liveness and readiness probe

* Set the security context for registry

* Add registry pvc access mode option

* registry add replica requirement check

* docs: add registry replicas setting note

* Update docs/kubernetes-apps/registry.md

Co-authored-by: Cristian Calin <6627509+cristicalin@users.noreply.github.com>

Co-authored-by: Cristian Calin <6627509+cristicalin@users.noreply.github.com>