Add a Status field on ImageRepository

When clients want to use internal ImageRepositories (an ImageRepository that
is backed by an OpenShift registry that can be automatically created on demand
when a user pushes or pulls to it) a client needs to be able to know what registry
URL that is in order to push images.

This pull adds a Status struct to an ImageRepository (as defined upstream) that
conveys the *real* DockerImageRepository name (vs the value set on creation or update
by a consumer).  It is populated by an ENV var set when OpenShift starts, but in the
future may be a special service in the default namespace.

When a client requests an ImageRepository, the "status.dockerImageRepository" will
be set to "dockerImageRepository" or to the value of `<defaultRegistry>/<namespace>/<name>`.  
A properly configured default registry would know how to lookup `<namespace>/<name>` 
when pulling the image.

@ncdc review