Stage Updatable Playbook

[marshall-sg]

Is your enhancement request related to a problem? Please describe.
Once started the playbook tool is static in its behavior. While this is desirable in many cases, it is also desirable to allow for dynamic modification. Specifically when the command currently running is large (won't finish quick) or costly (lose valuable data) to terminate for updating subsequent execution steps.

Describe the solution you'd like
The nmdb-playbook tool should support a dynamic mode that allows for checking the next stage to ensure modifications have not been made in the DB before executing. If modifications have been made it should use the updated configuration.

Describe alternatives you've considered
Generally, this can be accomplished by scripting. That is, continually query the data store for the next unfinished stage.