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/overmap/exoplanets/decor/_turfs.dm

@@ -5,7 +5,7 @@
 	has_resources = 1
 	footstep_sound = /singleton/sound_category/asteroid_footstep
 	turf_flags = TURF_FLAG_BACKGROUND
-	flags = null
+	turf_flags = null
 
 	does_footprint = TRUE
 

code/modules/overmap/exoplanets/exoplanet.dm

@@ -309,7 +309,7 @@
 			// Ruins check - try to avoid blowing up ruins with our LZ
 			// We do this until we run out of attempts
 			for(var/turf/check in block_to_check)
-				if(!istype(get_area(check), /area/exoplanet) || check.flags & TURF_NORUINS)
+				if(!istype(get_area(check), /area/exoplanet) || check.turf_flags & TURF_NORUINS)
 					valid = FALSE
 					break
 			// Landability check - try to find an already-open space for an LZ