This patch:
- removes unused method `common.utils:pretty_choice_list`;
- removes unused method `common.utils:find_resource`;
- removes unused method `common.utils:exit`;
- adds alias to `cliutils:args` in `common.utils`;
- adds alias to `cliutils:env` in `common.utils`;
- reuses method `print_list` from `cliutils`;
- reuses method `print_dict` from `cliutils`.
Related to blueprint common-client-library-2
Change-Id: I42318c6947509d4338309d03e722d822182bbc5d