Improves and cleans up TabletopSystem further. (#4633)

Content.Server/Tabletop/TabletopSessionPlayerData.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.Tabletop
+{
+    /// <summary>
+    ///     A class that stores per-player data for tabletops.
+    /// </summary>
+    public class TabletopSessionPlayerData
+    {
+        public EntityUid Camera { get; set; }
+    }
+}