Extract test-utils module

- removed duplicate code that was creating VesMessages
and similiar objects
- removed duplicate code in command line parsing tests
- made minor refactorings to avoid passing unnecessary params
and to be as verbose as possible in tests

Closes ONAP-699

Change-Id: I2607f1f775054ae1c5f275c231895f838b415371
Signed-off-by: fkrzywka <filip.krzywka@nokia.com>
Issue-ID: DCAEGEN2-601
24 files changed