chore: add room configs back in

At the moment, MC relies on some of these classes, so they are necessary
in Essentials for now. We can explore how to remove them at a later date

src/PepperDash.Essentials.Core/Room/Config/EssentialsHuddleRoomPropertiesConfig.cs

@@ -0,0 +1,34 @@
+using Newtonsoft.Json;
+
+namespace PDT.Plugins.Essentials.Rooms.Config
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public class EssentialsHuddleRoomPropertiesConfig : EssentialsRoomPropertiesConfig
+    {
+        /// <summary>
+        /// The key of the default display device
+        /// </summary>
+        [JsonProperty("defaultDisplayKey")]
+        public string DefaultDisplayKey { get; set; }
+
+        /// <summary>
+        /// The key of the default audio device
+        /// </summary>
+        [JsonProperty("defaultAudioKey")]
+        public string DefaultAudioKey { get; set; }
+
+        /// <summary>
+        /// The key of the source list for the room
+        /// </summary>
+        [JsonProperty("sourceListKey")]
+        public string SourceListKey { get; set; }
+
+        /// <summary>
+        /// The key of the default source item from the source list
+        /// </summary>
+        [JsonProperty("defaultSourceItem")]
+        public string DefaultSourceItem { get; set; }
+    }
+}