Implemented layer elements

Added a brush layer element
Corsair - Added ST100 RGB layout

src/Artemis.Core/Services/Interfaces/ILayerService.cs

@@ -0,0 +1,18 @@
+using Artemis.Core.Models.Profile;
+using Artemis.Core.Plugins.LayerElement;
+
+namespace Artemis.Core.Services.Interfaces
+{
+    public interface ILayerService : IArtemisService
+    {
+        /// <summary>
+        ///     Instantiates and adds the <see cref="LayerElement" /> described by the provided
+        ///     <see cref="LayerElementDescriptor" /> to the provided <see cref="Layer" />.
+        /// </summary>
+        /// <param name="layer">The layer to add the new layer element to</param>
+        /// <param name="layerElementDescriptor">The descriptor of the new layer element</param>
+        /// <param name="settings">JSON settings to be deserialized and injected into the layer element</param>
+        /// <returns></returns>
+        LayerElement InstantiateLayerElement(Layer layer, LayerElementDescriptor layerElementDescriptor, string settings = null);
+    }
+}