add namespace selector field to crq describe output

[juanvallejo]

Related bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1400912

This patch adds a Namespace Selector field to the describer output of clusterresourcequota to display the list of namespaces that are selected based on the clusterresourcequota's --project-anotation-selector.

Example

$ oc create clusterresourcequota crq-1 --project-annotation-selector=openshift.io/requester=user --hard=secrets=50

$ oc new-project p-1 --as=user
$ oc new-project p-2 --as=user
$ oc new-project p-3 --as=dev

$ oc describe clusterresourcequota crq-1
Name:           crq-1
Namespace:      <none>
Created:        52 minutes ago
Labels:         <none>
Annotations:    <none>
Namespace Selector: ["p-1" "p-2"]
Label Selector: <null>
AnnotationSelector: map[openshift.io/requester:user]
Resource        Used    Hard
--------        ----    ----
secrets         18      50

@openshift/cli-review

[juanvallejo]

[test]

[fabianofranz]

LGTM [merge]

[juanvallejo]

check flaked on #11024 re[test]

[juanvallejo]

conformance check flaked on #11662 re[test]

[juanvallejo]

conformance flaked on #11662 re[test]

[openshift-bot]

Evaluated for origin test up to b1a84eb

[openshift-bot]

continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/12551/) (Base Commit: 79cccd7)

[juanvallejo]

@fabianofranz could you re-tag please?

[fabianofranz]

[merge]

[openshift-bot]

Evaluated for origin merge up to b1a84eb

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/12570/) (Base Commit: 1134ff1) (Image: devenv-rhel7_5585)