Implement the ability to mark a projects and its questions as a "stealth" project

[SherRao]

Description

Refer to the parent ticket on what should be implemented, and the blocking ticket for what the UI should be.

Blocked by

• Design the ability to mark a project and its questions as a "stealth" project #707

Checklist

Before submitting this ticket, make sure this ticket:

• Is labelled properly - if this is a refactor, add the label!
• Has the SPUR project assigned to it.
• Has an assigned milestone.

And lastly:

• Once someone picks up this ticket, make sure to assign it.