Merge changes I4ecc5002,Iff21654e,I312be8e8

* changes:
  kube/kube.libsonnet: add OpenAPI.Require
  kube/kube.libsonnet: add Contain to Namespace
  kube/kube.libsonnet: add CertificateVolume

kube/kube.libsonnet

@@ -12,6 +12,20 @@ kube {
     Certificate(name): kube._Object("certmanager.k8s.io/v1alpha1", "Certificate", name) {
         spec: error "spec must be defined",
     },
+    # For use in PodSpec.volumes_
+    CertificateVolume(certificate): {
+        secret: { secretName: certificate.spec.secretName },
+    },
+
+    # Add .Contain method to Namespaces, allowing for easy marking of particular
+    # kube objects as contained in that namespace.
+    Namespace(name): kube.Namespace(name) {
+        Contain(o):: o {
+            metadata+: {
+                namespace: name,
+            },
+        },
+    },
 
     CephObjectStoreUser(name): kube._Object("ceph.rook.io/v1", "CephObjectStoreUser", name) {
         local user = self,
@@ -31,6 +45,10 @@ kube {
             openAPIV3Schema: obj.render,
         },
 
+        Required(inner):: inner {
+            required:: true,
+        },
+
         Dict:: {
             local dict = self,
             required:: false,