Fix findRandomWorld not accounting for satellites

src/main/kotlin/ru/dbotthepony/kstarbound/server/world/ServerUniverse.kt

@@ -152,7 +152,15 @@ class ServerUniverse private constructor(marker: Nothing?) : Universe(), Closeab
 			val y = random.nextRange(baseInformation.xyCoordRange)
 
 			val result = scanSystems<UniversePos>(rect + Vector2i(x, y)) {
-				val children = children(it)
+				val children = ArrayList<UniversePos>()
+
+				for (planet in children(it)) {
+					children.add(planet)
+
+					for (satellite in children(planet)) {
+						children.add(satellite)
+					}
+				}
 
 				if (children.isEmpty())
 					return@scanSystems KOptional()