Add UnmarshalDescriptionJSON method to SiteMirrorImageStatus
Add DescriptionReplayStatus method to SiteMirrorImageStatus
Both these functions are meant to help extract the JSON object that is
some times appended to the Description field in the
SiteMirrorImageStatus struct. I have only seen the JSON appear after
"replaying, " but there's little docs for this and I skimmed to code to
even find out what fields the JSON might include. As such, the
UnmarshalDescriptionJSON tries to unmarshal the appended JSON into an
object the caller provides in case skimming the code was insufficient or
the caller has other needs. For most cases, DescriptionReplayStatus can
be used to parse the JSON into a struct containing known fields.
Signed-off-by: John Mulligan <jmulligan@redhat.com>