somebody can audit and unblock projects

As a head of department, I want to unblock a project after auditing it.

If the project is ok, I want to make it visible to the public by removing the "blocked" flag.

This also freezes the project: a student can no longer edit the project. They can unfreeze it, but then it goes back to being blocked and not visible to the public.

• change wording draft vs. public to draft vs. ready
• in the project/show view: teacher can unblock the project. this also freezes the project, nobody can't edit
• if one of the team members wants to edit, they can switch the project back to being blocked, but then it will no longer be public