Ports the weather system from Nebula. (#18706)

* part 1

* compiles?

* IT WORKS

* vis contents

* fixes

* umbrelloid

* umbrella 2

* dsasdd

* stuff

* lmao

---------

Co-authored-by: Matt Atlas <liermattia@gmail.com>

code/modules/abstract/_abstract.dm

@@ -0,0 +1,21 @@
+/obj/abstract
+	name          = ""
+	icon          = 'icons/effects/landmarks.dmi'
+	icon_state    = "x2"
+	simulated     = FALSE
+	density       = FALSE
+	anchored      = TRUE
+	abstract_type = /obj/abstract
+	invisibility  = INVISIBILITY_ABSTRACT
+
+/obj/abstract/Initialize()
+	. = ..()
+	verbs.Cut()
+	//Let mappers see the damn thing by just making them invisible here
+	opacity       =  FALSE
+	alpha         =  0
+	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
+
+/obj/abstract/ex_act()
+	SHOULD_CALL_PARENT(FALSE)
+	return

code/modules/abstract/abstract_exterior_marker.dm

@@ -0,0 +1,21 @@
+/obj/abstract/exterior_marker
+	var/set_outside
+
+/obj/abstract/exterior_marker/Initialize()
+	..()
+	var/turf/T = loc
+	if(istype(T))
+		T.set_outside(set_outside)
+	return INITIALIZE_HINT_QDEL
+
+/obj/abstract/exterior_marker/outside
+	name = "Outside"
+	set_outside = OUTSIDE_NO
+
+/obj/abstract/exterior_marker/inside
+	name = "Inside"
+	set_outside = OUTSIDE_YES
+
+/obj/abstract/exterior_marker/use_area
+	name = "Use Area Outside"
+	set_outside = OUTSIDE_AREA

code/modules/abstract/abstract_weather_marker.dm

@@ -0,0 +1,16 @@
+/obj/abstract/weather_marker
+	name = "Weather Marker"
+	/// The weather type we want. This needs to be a weather singleton type, such as /singleton/state/weather/rain/storm.
+	/// These should be used for forcing weather in an away site or an event map.
+	var/weather_type
+
+/obj/abstract/weather_marker/Initialize()
+	..()
+	return INITIALIZE_HINT_LATELOAD
+
+/obj/abstract/weather_marker/LateInitialize()
+	. = ..()
+	if(!ispath(weather_type))
+		log_debug("Invalid weather type mapped in at [x] [y] [z]!")
+		return INITIALIZE_HINT_QDEL
+	SSweather.setup_weather_system(z, weather_type)