Add the ability to archive users

This is a suggestion for a feature that would be very useful for organizations with staff turn-over. I'm imagining a one-step "archive" command for users that would: 1) strip the user of all permissions, 2) prevent the user from logging in, 3) disallow assigning issues to the user. The difference between this and deleting the user is that issues that are currently assigned to the user or were reported by the user would retain the link back to the user. An extra bonus would be if an interim screen allowed you to bulk reassign (or unassign) any issues currently assigned to the user when you perform the archive.