Add common code for CLI tools

This code is shared between python-*client packages and is
used in CLI tools (nova, glance, etc.):
* decorators: arg and unauthenticated;
* print_list and print_dict;
* get_password.

This code comes from novaclient/utils.py.

Implements: blueprint common-cli-utils

Change-Id: Ic4fd6b0e3539032b5839eaa0ca23e5fa16ce47e2
Merge "Add common code for CLI tools"