Unified command execution and unit tests

- All arguments inits moved to own clases
- Added unified way to execute commands
- Unit test structure and very basic tests
- Command line script to test coverage

Change-Id: I10bc973776595779b563b84548d46367bcd0886f
Related-PROD: PROD-28199
diff --git a/cfg_checker/modules/packages/versions.py b/cfg_checker/modules/packages/versions.py
index 9352dd6..9737d80 100644
--- a/cfg_checker/modules/packages/versions.py
+++ b/cfg_checker/modules/packages/versions.py
@@ -1,7 +1,8 @@
 import csv
 import os
 
-from cfg_checker.common import config, const, logger_cli, pkg_dir
+from cfg_checker.common import config, const, logger_cli
+from cfg_checker.common.settings import pkg_dir
 
 
 class PkgVersions(object):