"oc config use-context" should complete contexts

[commonquail]

kubectl config use-context can complete contexts. oc config use-context cannot. Being able to complete contexts would be quite helpful in its own right, but especially so since oc login clobbers kubeconfig contexts while simultaneously oc breaks kubectl's ability to complete contexts.

One way to accomplish this would be to piggy-back kubectl's context completion by adding.

        oc_config_use-context | oc_config_rename-context)
            __kubectl_config_get_contexts
            return
            ;;

to __custom_func, and optionally

    flags_with_completion+=("--context")
    flags_completion+=("__kubectl_config_get_contexts")

after every

    flags+=("--context=")

The downside to that approach is the dependency on kubectl completion, without which you get something like

$ oc config use-context <tab>__kubectl_config_get_contexts: command not found

oc create clusterrolebinding already delegates to __kubectl_get_resource_clusterrule so there is precedence, however, I'd personally consider contexts to be a far more prominent concept than cluster role bindings.

In a similar vein, clusters and users could be completed with __kubectl_config_get_clusters and __kubectl_config_get_users.

An even simpler way to resolve this is to resolve #371 and declare these completions outside of oc's scope.

[openshift-bot]

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[commonquail]

/remove-lifecycle stale

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
Exclude this issue from closing by commenting /lifecycle frozen.

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/lifecycle stale

[commonquail]

/remove-lifecycle stale

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
Exclude this issue from closing by commenting /lifecycle frozen.

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/lifecycle stale

[commonquail]

/remove-lifecycle stale

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
Exclude this issue from closing by commenting /lifecycle frozen.

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/lifecycle stale

[openshift-bot]

Stale issues rot after 30d of inactivity.

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/lifecycle rotten
/remove-lifecycle stale

[commonquail]

/remove-lifecycle rotten
/lifecycle frozen