refactor: routing interfaces and implementations to support current sources

- Updated ICurrentSources interface to use IRoutingSource instead of SourceListItem.
- Introduced CurrentSourcesChangedEventArgs for detailed event notifications.
- Modified IRoutingOutputs and IRoutingSource interfaces to include JSON properties for serialization.
- Enhanced IRoutingSink and related interfaces to implement ICurrentSources for better source management.
- Refactored RoutingFeedbackManager to utilize new current source handling.
- Updated GenericAudioOut, GenericSink, and BlueJeansPc classes to implement new current source logic.
- Adjusted MobileControl messengers to accommodate changes in current source handling.
- Removed deprecated destination handling in MobileControlEssentialsRoomBridge.

src/PepperDash.Essentials.Core/Devices/DestinationListItem.cs

@@ -2,6 +2,7 @@
 
 using Newtonsoft.Json;
 using PepperDash.Essentials.Core;
+using PepperDash.Essentials.Core.Routing;
 
 namespace PepperDash.Essentials.Core;
 
@@ -11,23 +12,22 @@ namespace PepperDash.Essentials.Core;
 /// </summary>
 public class DestinationListItem
 {
-
     /// <summary>
     /// Gets or sets the key identifier for the sink device that this destination represents.
     /// </summary>
     [JsonProperty("sinkKey")]
     public string SinkKey { get; set; }
 
-    private EssentialsDevice _sinkDevice;
+    private IRoutingSink _sinkDevice;
 
     /// <summary>
     /// Gets the actual device instance for this destination. 
     /// Lazily loads the device from the DeviceManager using the SinkKey.
     /// </summary>
     [JsonIgnore]
-    public EssentialsDevice SinkDevice
+    public IRoutingSink SinkDevice
     {
-        get { return _sinkDevice ?? (_sinkDevice = DeviceManager.GetDeviceForKey(SinkKey) as EssentialsDevice); }
+        get { return _sinkDevice ?? (_sinkDevice = DeviceManager.GetDeviceForKey(SinkKey) as IRoutingSink); }
     }
 
     /// <summary>

src/PepperDash.Essentials.Core/Devices/SourceListItem.cs

@@ -43,17 +43,17 @@ public class SourceListItem
     /// Returns the source Device for this, if it exists in DeviceManager
     /// </summary>
     [JsonIgnore]
-    public Device SourceDevice
+    public IRoutingSource SourceDevice
     {
         get
         {
             if (_SourceDevice == null)
-                _SourceDevice = DeviceManager.GetDeviceForKey(SourceKey) as Device;
+                _SourceDevice = DeviceManager.GetDeviceForKey<IRoutingSource>(SourceKey);
             return _SourceDevice;
         }
     }
 
-    private Device _SourceDevice;
+    private IRoutingSource _SourceDevice;
 
     /// <summary>
     /// Gets either the source's Name or this AlternateName property, if