Make archived projects a separate tab

[jmgasper]

On the "Project Management" view, let's remove the "Toggle Archived Projects" button and replace it with the same sort of tab mechanism we added to "Git access control".

There will be two tabs:

• "Current Projects"
• "Archived Projects"

We won't load the archived projects until the user actually clicks the tab, to ensure proper performance when loading this page, since archived projects will be rarely shown.