Go to bottom of Fray's End after tutorial

[wjt]

The old intro used to take the player to the bottom island of Fray's End
rather than taking them to right outside the loom. This was removed in
the new tutorial because CollectibleItem didn't have a way to specify a
spawn point in the target scene.

Now it does: do so.

Helps #2186

[wjt]

As described on #2186 I imagine we should have Arun be in Fray's End as well, but I don't want to change Fray's End while @manuq is working on a big branch touching it - I've already done that more than once and I feel bad :)

[github-actions]

Play this branch at https://play.threadbare.game/branches/endlessm/wjt/go-to-bottom-of-fray-s-end-after-tutorial/.

(This launches the game from the start, not directly at the change(s) in this pull request.)