client/qserv_admin_impl.py: I know the czar's Python code is ugly. But the concept of having more than one entry point for users is also ugly. I feel like the client should just wrap up stuff into JSON and make a REST call into the czar. Ideally the proxy would use REST, perhaps via: https://github.com/fperrad/lua-Spore/, which at least seems more thought-out than lua-xmlrpc.

(This came up in the review of DM-56, the review comments are captured in DM-225)