feat: Update .gitignore and enhance routing-related classes

- Updated `.gitignore` to include additional files and directories.
- Added summary comments and new properties in `LevelControlListItem.cs` for better clarity and functionality.
- Enhanced documentation in `SourceListItem.cs` and introduced new properties, including `Destinations` and a `ToString` method.
- Introduced `SourceRouteListItem` class with routing properties and expanded `eSourceListItemDestinationTypes` enum.
- Added `IRoutingSinkWithInputPort` interface in `IRoutingSink.cs` to support input port functionality.

src/PepperDash.Essentials.Core/Routing/IRoutingSink.cs

@@ -7,8 +7,14 @@
     {        
     }
 
+    /// <summary>
+    /// For fixed-source endpoint devices with an input port
+    /// </summary>
     public interface IRoutingSinkWithInputPort :IRoutingSink
     {
+        /// <summary>
+        /// Gets the current input port for this routing sink.
+        /// </summary>
         RoutingInputPort CurrentInputPort { get; }
     }
     /*/// <summary>