Make closets lazy-initialize their default contents

[out-of-phaze]

Description of changes

Do not merge, needs additional testing and maintainer consensus on if this is something we even want to do. Could also make it a config or compile option if desired.

Most closets will now wait until their first interaction (with their contents, not necessarily by players) to create their contents.

Notably, this will cause issues for a few things like in worlds, which is why I want maintainer consensus about what, if anything, to do about that sort of thing.

Why and what will this PR improve

Cuts off a decent amount of init time by waiting to create objects that functionally don't exist until interacted with already.

Changelog

:cl: experiment: Closets will not initialize their contents until first interacted with, which makes startup faster but could cause bugs. Report any issues on the issue tracker! /:cl: