Implement some kind of project archive for "finished" projects

[witbok]

Eventually (we hope) projects should be completed, or at least become inactive.

There's no way to mark this on the website.

[ZacharyRSmith]

I've requested a pull that does some of this. However, we still need to add the ability for one to merely go to a project's edit page and mark it as finished.

[rabidaudio]

#27

[ZacharyRSmith]

Ah sorry, I didn't know that a pull request makes an issue number. I will comment that next time!

[rabidaudio]

Haha yeah, I only learned about that last week