Split up and rename var/flags (#17794)

* Split up and rename `var/flags`

* Various fixes

* CL

* Don't rename Phoron Guard phoron preset

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

code/modules/materials/material_sheets.dm

@@ -42,7 +42,7 @@
 		pickup_sound = material.pickup_sound
 
 	if(material.conductive)
-		flags |= CONDUCT
+		obj_flags |= OBJ_FLAG_CONDUCTABLE
 
 	matter = material.get_matter()
 

code/modules/materials/materials.dm

@@ -561,7 +561,7 @@
 					to_chat(user, "<span class='warning'>This material is not reinforced enough to use for a door.</span>")
 					return
 				for(var/obj/obstacle in T)
-					if((obstacle.flags & ON_BORDER) && obstacle.dir == user.dir)
+					if((obstacle.atom_flags & ATOM_FLAG_CHECKS_BORDER) && obstacle.dir == user.dir)
 						failed_to_build = 1
 	if(failed_to_build)
 		to_chat(user, "<span class='warning'>There is no room in this location.</span>")