This commit refactors trait system for guest types. Namely, as discussed offline on zulip, `GuestType` now includes `GuestTypeClone`, whereas `GuestTypeCopy` has been renamed to `GuestTypeTransparent`.
This commit refactors trait system for guest types. Namely, as discussed offline on zulip, `GuestType` now includes `GuestTypeClone`, whereas `GuestTypeCopy` has been renamed to `GuestTypeTransparent`.