Improves belt item overlay code, Adds new belt item overlay sprites (#17568)

* belt-improvements-and-sprites

* fixes my fix of botany belt allowed contents

code/game/objects/items/tools/screwdriver.dm

@@ -4,6 +4,7 @@
 	desc = "You can be totally screwy with this."
 	icon = 'icons/obj/tools.dmi'
 	icon_state = "screwdriver_map"
+	belt_icon = "screwdriver"
 	flags = CONDUCT
 	slot_flags = SLOT_BELT
 	force = 5
@@ -74,6 +75,7 @@
 	desc = "A simple hand drill with a screwdriver bit attached."
 	icon_state = "drill_screw"
 	item_state = "drill"
+	belt_icon = "hand_drill"
 	materials = list(MAT_METAL=150,MAT_SILVER=50,MAT_TITANIUM=25)
 	origin_tech = "materials=2;engineering=2" //done for balance reasons, making them high value for research, but harder to get
 	force = 8 //might or might not be too high, subject to change