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/helpers/args_utils.py b/cfg_checker/helpers/args_utils.py
index f8453e4..daf55b1 100644
--- a/cfg_checker/helpers/args_utils.py
+++ b/cfg_checker/helpers/args_utils.py
@@ -1,8 +1,16 @@
+import argparse
 import os
+import sys
 
 from cfg_checker.common.exception import ConfigException
 
 
+class MyParser(argparse.ArgumentParser):
+    def error(self, message):
+        sys.stderr.write('Error: {0}\n\n'.format(message))
+        self.print_help()
+
+
 def get_arg(args, str_arg):
     _attr = getattr(args, str_arg)
     if _attr: