[Projects Beta] Make drafts private

[chiefmikey]

Just a suggestion that I personally would be happy to see: having the option to set drafts as private in a public project.

All of my projects that are associated with a repo are public and I use them to create new issues and track progress, which I think is helpful for contributors to see. But I also often throw a quick draft into the backlog with a very rough title and description to not lose a fleeting idea for a feature or a random bug realization that I'll come back to later and properly create an issue for.

Currently, those drafts are publicly visible in my projects littered along with the actual issues. It would be great for me if those drafts could be private while keeping the rest of the issues in the project public!