[CONTENT_UPDATE] Update K8s/OpenShift terminology in Che, CRW docs

See https://github.com/openshift/openshift-docs/blob/master/contributing_to_docs/term_glossary.adoc for new spelling (capitalization) of K8s/OpenShift terms.

In short, almost all terms (except Operator) are now lowercase, unless a specific API object is referenced – then it's CamelCase in monospace font (in backticks: ``).

When replacing, be careful not to change console outputs, config files, etc.