Add the ability for mappers to drag grids around. (#7769)

* Add the ability for mappers to drag grids around.

* Less message spam

* Also flinging

Content.Server/Maps/GridDraggingSystem.cs

@@ -0,0 +1,42 @@
+using Content.Shared.Maps;
+using Robust.Server.Console;
+using Robust.Server.Player;
+
+namespace Content.Server.Maps;
+
+/// <inheritdoc />
+public sealed class GridDraggingSystem : SharedGridDraggingSystem
+{
+    [Dependency] private readonly IConGroupController _admin = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeNetworkEvent<GridDragRequestPosition>(OnRequestDrag);
+        SubscribeNetworkEvent<GridDragVelocityRequest>(OnRequestVelocity);
+    }
+
+    private void OnRequestVelocity(GridDragVelocityRequest ev, EntitySessionEventArgs args)
+    {
+        if (args.SenderSession is not IPlayerSession playerSession ||
+            !_admin.CanCommand(playerSession, CommandName) ||
+            !Exists(ev.Grid) ||
+            Deleted(ev.Grid)) return;
+
+        var gridBody = Comp<PhysicsComponent>(ev.Grid);
+        gridBody.LinearVelocity = ev.LinearVelocity;
+        gridBody.AngularVelocity = 0f;
+    }
+
+    private void OnRequestDrag(GridDragRequestPosition msg, EntitySessionEventArgs args)
+    {
+        if (args.SenderSession is not IPlayerSession playerSession ||
+            !_admin.CanCommand(playerSession, CommandName) ||
+            !Exists(msg.Grid) ||
+            Deleted(msg.Grid)) return;
+
+        var gridXform = Transform(msg.Grid);
+
+        gridXform.WorldPosition = msg.WorldPosition;
+    }
+}