Medical gown in loadout + sprite replacement (#21516)

Adds the medical patient gown to the loadout, locked to offduty and
passenger only, intended to be used for characters staying in the
medical ward. The sprites are also replaced with ones from Bay,
alongside adding 2 new preset colored versions.

### Asset Licenses
The following assets that **have not** been created by myself are
included in this PR:

Replacement icons are by [AtomicWorm](https://github.com/AtomicWorm)
from Baystation https://github.com/Baystation12/Baystation12/pull/25436

code/modules/client/preference_setup/loadout/items/uniform.dm

@@ -340,6 +340,13 @@
 
 	gear_tweaks += new /datum/gear_tweak/path(dress_colorable)
 
+/datum/gear/uniform/miscellaneous/medical_gown
+	display_name = "medical gown"
+	description = "A loose piece of clothing, commonly worn by medical patients."
+	path = /obj/item/clothing/under/medical_gown
+	flags = GEAR_HAS_NAME_SELECTION | GEAR_HAS_DESC_SELECTION | GEAR_HAS_COLOR_SELECTION
+	allowed_roles = list("Off-Duty Crew Member", "Passenger")
+
 /*
 	Uniform Rolled State Adjustment
 */