deploy: prompt for missing values

[joshk0]

Moved from pre-OSS repository

Probably kdt's biggest downside right now is it doesn't guide you through setting the many deploy values which are needed to run a deploy:

• job
• build number (latest vs specific number)
• artifacts (from specific list of artifacts in that build number)
• flavors (from specific list of flavors in that build number)
• context (could be defaulted in the deploy.yaml for a given artifact)
• dry run

If it could interactively prompt for the ones which were missing and needed to be fill in, and intelligently give you options based on the actual available values for a specific build, it would probably increase usability a ton.