Split up and rename var/flags (#17794)

* Split up and rename `var/flags`

* Various fixes

* CL

* Don't rename Phoron Guard phoron preset

---------

Co-authored-by: Cody Brittain <cbrittain10@live.com>

code/game/objects/items/weapons/material/caltrops.dm

@@ -24,7 +24,7 @@
 			return
 		if(H.resting)
 			return
-		if(H.shoes?.item_flags & LIGHTSTEP)
+		if(H.shoes?.item_flags & ITEM_FLAG_LIGHT_STEP)
 			return
 
 		to_chat(H, SPAN_DANGER("You step on \the [src]!"))

code/game/objects/items/weapons/material/knives.dm

@@ -7,7 +7,7 @@
 	contained_sprite = TRUE
 	icon_state = "knife"
 	desc = "A general purpose Chef's Knife made by SpaceCook Incorporated. Guaranteed to stay sharp for years to come."
-	flags = CONDUCT
+	obj_flags = OBJ_FLAG_CONDUCTABLE
 	sharp = 1
 	edge = TRUE
 	var/active = 1 // For butterfly knives

code/game/objects/items/weapons/material/twohanded.dm

@@ -351,7 +351,7 @@
 	desc = "A robust tree-cutting chainsaw intended to cut down various types of invasive spaceplants that grow on the station."
 	icon_state = "chainsaw_off"
 	base_icon = "chainsaw_off"
-	flags = CONDUCT
+	obj_flags = OBJ_FLAG_CONDUCTABLE
 	force = 10
 	force_unwielded = 10
 	force_wielded = 20