Fixes #5794 : Improve how Async commands are done in katello-cli.

The main use case driving this is subscription upload --organization-label.

This is a replacement for https://github.com/Katello/hammer-cli-katello/pull/169.
I am not sure why this does not apply, but it does not.
Merge pull request #179 from bkearney/bkearney/5794

Fixes #5794 : Improve how Async commands are done in katello-cli.