Python logging improvements, plus changes to handle different return value from cnx-user

this is primarily cleaning up the python logging (ie on failure).  This is done to prepare the ground for the next pull-request on providing a logging API

We remove the log.py common module, and revert to using a global declaration of logging in each module.
We also adapt the testing so we are able to test without reaching through to the database first.

We also alter the user_dict which holds metadata about a user to *only* hold the UUID that is returned by cnx-user and is system global identifier for a user.  (ie repo knows nothing about a user)