Adds lava exoplanets (#15023)

code/modules/maps/planet_types/lava.dm

@@ -0,0 +1,38 @@
+/obj/effect/overmap/visitable/sector/exoplanet/lava
+	name = "lava exoplanet"
+	desc = "An exoplanet with a lot of volcanic activity."
+	color = "#575d5e"
+	planetary_area = /area/exoplanet/barren
+	rock_colors = list(COLOR_DARK_GRAY)
+	possible_themes = list(/datum/exoplanet_theme/mountains)
+	map_generators = list(/datum/random_map/noise/exoplanet/lava, /datum/random_map/noise/ore)
+	ruin_tags_blacklist = RUIN_HABITAT|RUIN_WATER
+	features_budget = 3
+	surface_color = "#575d5e"
+	water_color = null
+
+/obj/effect/overmap/visitable/sector/exoplanet/lava/generate_habitability()
+	return HABITABILITY_BAD
+
+/obj/effect/overmap/visitable/sector/exoplanet/lava/generate_atmosphere()
+	..()
+	atmosphere.remove_ratio(0.9)
+
+/obj/effect/overmap/visitable/sector/exoplanet/lava/get_surface_color()
+	return "#575d5e"
+
+/datum/random_map/noise/exoplanet/lava
+	descriptor = "lava exoplanet"
+	smoothing_iterations = 4
+	land_type = /turf/unsimulated/floor/asteroid/basalt
+	water_type = /turf/simulated/lava
+	water_level_min = 3
+	water_level_max = 5
+	flora_prob = 0
+	flora_diversity = 0
+	fauna_prob = 0
+
+/area/exoplanet/lava
+	name = "\improper Planetary surface"
+	ambience = AMBIENCE_LAVA
+	base_turf = /turf/unsimulated/floor/asteroid/basalt