This PR does the following:
- migrated ~/.dockerfg to ~/.docker/config.json. The data is migrated
but the old file remains in case its needed
- moves the auth json in that fie into an "auth" property so we can add new
top-level properties w/o messing with the auth stuff
- adds support for an HttpHeaders property in ~/.docker/config.json
which adds these http headers to all msgs from the cli
In a follow-on PR I'll move the config file process out from under
"registry" since it not specific to that any more. I didn't do it here
because I wanted the diff to be smaller so people can make sure I didn't
break/miss any auth code during my edits.
Signed-off-by: Doug Davis <dug@us.ibm.com>