Allow specification of "manual-ness" of stage per branch plan

I may already have a workaround for this, but the intent here is around a workflow where artifacts are published to a central repository, in this case Maven;

The primary plan runs against the development line and drops -SNAPSHOT builds to maven, and should automatically do so; however, a release branch should have the mvn deploy call be a manual step to allow for review.

Another example of where this would be useful is for situations where a development build publishes to a development server, but a production build should pause before deployment to the production server - deployment location is parameterized to allow variation in the final location.