#1462 extracted MapGrid's HasGravity property to separate Content com… (#4200)

* #1462 extracted MapGrid's HasGravity property to separate Content component

* #1462 - PR suggestions

* Merge to master

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Client/Gravity/GravitySystem.cs

@@ -0,0 +1,9 @@
+using Content.Shared.Gravity;
+
+namespace Content.Client.Gravity
+{
+    internal sealed class GravitySystem : SharedGravitySystem
+    {
+
+    }
+}