Ports a rewritten version of BAYSTRUMENTS (#11680)

* bay instruments

* k

* AAA

* remove that

* changes

* Update _instrument_key.dm

* safety nets

* @ghommie fixed

* volume

* Update item.dm

* Update item.dm

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

_maps/RandomZLevels/Cabin.dmm

@@ -713,7 +713,7 @@
 /turf/open/floor/wood,
 /area/awaymission/cabin)
 "cz" = (
-/obj/structure/piano,
+/obj/structure/musician/piano,
 /turf/open/floor/wood,
 /area/awaymission/cabin)
 "cA" = (