registry: default --insecure-registry to localhost and 127.0.0.1

Signed-off-by: Johan Euphrosine <proppy@google.com>
registry: always treat 127.0.0.1 as insecure for all cases anytime anywhere

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Merge pull request #9124 from erikh/secure-localhost

Secure localhost registry (carry of #8898)