Add all websocket messages to generated openapi spec (#9682)

* Add all websocket messages to generated openapi spec

* Use oneOf

* JsonIgnore ServerId

* Oops

* Add discriminators

* Add WebSocketMessage container for Inbound and Outbound messages

MediaBrowser.Model/SyncPlay/SyncPlayQueueItem.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace MediaBrowser.Model.SyncPlay
+{
+    /// <summary>
+    /// Class QueueItem.
+    /// </summary>
+    public class SyncPlayQueueItem
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SyncPlayQueueItem"/> class.
+        /// </summary>
+        /// <param name="itemId">The item identifier.</param>
+        public SyncPlayQueueItem(Guid itemId)
+        {
+            ItemId = itemId;
+        }
+
+        /// <summary>
+        /// Gets the item identifier.
+        /// </summary>
+        /// <value>The item identifier.</value>
+        public Guid ItemId { get; }
+
+        /// <summary>
+        /// Gets the playlist identifier of the item.
+        /// </summary>
+        /// <value>The playlist identifier of the item.</value>
+        public Guid PlaylistItemId { get; } = Guid.NewGuid();
+    }
+}