Add Smoke and Foam chemical reaction effects. (#2913)

* Adds smoke reaction effect

* smoke tweaks

* address reviews

* Smoke fix

* Refactor smoke and add foam

* Fix stuff

* Remove thing

* Little things

* Address some comments

* Address more things

* More addressing

* License stuff

* Address refactor request

* Small things

* Add nullability

* Update Content.Server/GameObjects/EntitySystems/SolutionAreaEffectSystem.cs

Co-authored-by: Paul Ritter <ritter.paul1@googlemail.com>

Content.Server/Chemistry/ReactionEffects/SmokeAreaReactionEffect.cs

@@ -0,0 +1,16 @@
+#nullable enable
+using Content.Server.GameObjects.Components.Chemistry;
+using JetBrains.Annotations;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Server.Chemistry.ReactionEffects
+{
+    [UsedImplicitly]
+    public class SmokeAreaReactionEffect : AreaReactionEffect
+    {
+        protected override SolutionAreaEffectComponent? GetAreaEffectComponent(IEntity entity)
+        {
+            return entity.GetComponentOrNull<SmokeSolutionAreaEffectComponent>();
+        }
+    }
+}