Note that this assumes that both (docker login) and (oc login) has
happened, the credentials can be read from the usual config files,
and that the default OpenShift instance should be used.
This includes copy&pasted/modified/simplified code from OpenShift
and Kubernetes, primarily for config file parsing and setting up
TLS and HTTP authentication.
This is much smaller than linking to the upstream OpenShift client
libraries, which via various abstractions and registration drag in much
(dozens of megabytes) more code.
The primary loss from this simplification is automatic conversions
between various versions of the API objects, both for the REST API and
for local configuration storage.
This does not contain downloading/uploading signatures, which depends on
server-side support.
