[IDB Ignore] Centralize HUD icon file location (#22464)

Moves all HUD screen object icon files from various scattered locations
to icons/hud. No changes made to any icon_states in this PR, no
player-facing changes. Part of larger icon organization work and in
preparation for action button rework.

code/modules/psionics/interface/ui.dm

@@ -1,5 +1,5 @@
 /atom/movable/screen/psi
-	icon = 'icons/mob/screen/psi.dmi'
+	icon = 'icons/hud/mob/psi.dmi'
 	var/mob/living/owner
 	var/hidden = TRUE