Click Drag Functionality + Refactor Interaction Interfaces (#1125)

Co-authored-by: Víctor Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>
Co-authored-by: ComicIronic <comicironic@gmail.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Server/GameObjects/EntitySystems/GravitySystem.cs

@@ -16,7 +16,7 @@ using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Random;
 
-namespace Content.Server.GameObjects.EntitySystems
+namespace Content.Server.Interfaces.GameObjects.Components.Interaction
 {
     [UsedImplicitly]
     public class GravitySystem: EntitySystem