Print user warnings to command line output

[sergsalatsky]

Maintainers will complete the following section

• [x] Commit messages are descriptive enough
• [x] Code coverage from testing does not decrease and new code is covered
• [x] JSON/YAML configuration changes are updated in the relevant schema
• [x] Pull request has a link to an osbs-docs PR for user documentation updates

[sergsalatsky]

Release notes: Both the task result and command-line output could contain user warnings