[DOC OCP] Remove the documentation sections about Minishift / oc cluster up

Minishift / oc cluster up can be used to run Openshift 3.11 based on Kubernetse 1.11. We do not support it anymore. So it should be removed from the docs.

In particular, this includes this section: https://strimzi.io/docs/operators/latest/deploying.html#deploy-alternatives_str ... from the 3.5.2 section, only the {oc and kubectl commands}} part is really needed.