zli: debug messages for calls being made by zli

[andaaron]

Is your feature request related to a problem? Please describe. Sometimes it may be hard to troubleshoot why certain zli commands don't work as intended. For example the zot server may be a and older version from the zli, and not support newer extensions. Also the zli user may not have access to the zot logs.

Describe the solution you'd like It would be useful to have a debug option in zli, and when this debug option is used to show the actual calls being made from zli side, as well as responses. I'm thinking of something similar to the skopeo command line option for debug.