Root atoms should be put back in a loading state on bootstrap root unmount

[nebrius]

When a bootstrap root unmounts, we currently leave the root atom in it's loaded state. This means that bootstrap data won't be re-initialized if the bootstrap root is later mounted again. This could break client-side routing in some cases when a user navigates away from a page and then back to it.

I briefly looked at getting this to work, but it's not yet obvious the best way to do this.