make `oc` reuse the tokenrequest code from library-go

Library-go contains code for creating token requests that should be reused by all OpenShift components. Because of time-constraints, this code did not make it to `oc` in the past.

Fix that to prevent code out-of-sync issues.

4.14

100%

1. see if https://github.com/openshift/oc/pull/991 merged

it hasn't merged at the time of writing this bug

it's merged