The maintenance crate spawning crate is now a spawner (#80083)

## About The Pull Request

`/obj/structure/closet/crate/maint` was a type of crate that spawned a
completely different crate, and then deleted itself. I have decided to
swap this out for an actual spawning effect.

I have also did some subtypery to remove some duplicate code that
handled randomly opening the spawned closet/crate (through I am not that
satisfied with
`/obj/effect/spawner/random/structure/closet_empty/crate/with_loot` as a
sensible typepath name, I would like to ask for suggestions). I also
removed a loot define, because it was no longer needed as its contents
were used on a single page.

## Why It's Good For The Game

Things that act like spawners should be spawners.

Maybe this fixes the CI issue on northstar where a mousetrap box gets
deleted before it initializes during create and destroy? It was placed
above a spawner that spawned one of these self deleting crates. I am
unsure, I could not replicate this issue during testing.

## Changelog

Nothing player facing.

tools/UpdatePaths/Scripts/80083_crate_spawner_rework.txt

@@ -0,0 +1,2 @@
+/obj/structure/closet/crate/maint : /obj/effect/spawner/random/structure/closet_empty/crate/with_loot{@OLD}
+/obj/effect/spawner/random/structure/crate_empty : /obj/effect/spawner/random/structure/closet_empty/crate{@OLD}