New core landing animation

core/src/mindustry/game/Rules.java

@@ -109,6 +109,8 @@ public class Rules{
     public Team defaultTeam = Team.sharded;
     /** team of the enemy in waves/sectors. */
     public Team waveTeam = Team.crux;
+    /** color of clouds that is displayed when the player is landing */
+    public Color cloudColor = new Color(0f, 0f, 0f, 0f);
     /** name of the custom mode that this ruleset describes, or null. */
     public @Nullable String modeName;
     /** Whether cores incinerate items when full, just like in the campaign. */