Added shadows debug view

ScriptableRenderPipeline/LightweightPipeline/LWRP/Data/LightweightPipelineAsset.cs

         Normals,
         Metallness,
         Smoothness,
-        Occlusion
+        Occlusion,
+        Shadows
     };
 
     public class LightweightPipelineAsset : RenderPipelineAsset

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightPipeline.cs

                 case DebugViewMode.Occlusion:
                     LightweightShaderUtils.SetDebugMode(cmd, DebugViewKeyword.OCCLUSION);
                     break;
+                case DebugViewMode.Shadows:
+                    LightweightShaderUtils.SetDebugMode(cmd, DebugViewKeyword.SHADOWS);
+                    break;
             }
             context.ExecuteCommandBuffer(cmd);
             CommandBufferPool.Release(cmd);

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightShaderUtils.cs

         NORMALS,
         SMOOTHNESS,
         OCCLUSION,
+        SHADOWS,
 
         NUM_VIEWS
     }
             "_DEBUG_METALNESS",
             "_DEBUG_NORMALS",
             "_DEBUG_SMOOTHNESS",
-            "_DEBUG_OCCLUSION"
+            "_DEBUG_OCCLUSION",
+            "_DEBUG_SHADOWS"
         };
 
         public static string GetShaderPath(ShaderPathID id)

ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/LightweightPassLit.hlsl

 #elif defined(_DEBUG_OCCLUSION)
     ApplySSAO(surfaceData.occlusion, IN.shadowCoord);
     debug = surfaceData.occlusion;
+#elif defined(_DEBUG_SHADOWS)
+    debug = RealtimeShadowAttenuation(IN.shadowCoord);
 #endif
     return half4(debug, 1);
 }

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightStandard.shader

             // GPU Instancing
             #pragma multi_compile_instancing
 
-            #pragma multi_compile _ _DEBUG_ALBEDO _DEBUG_METALNESS _DEBUG_NORMALS _DEBUG_SMOOTHNESS _DEBUG_OCCLUSION
+            #pragma multi_compile _ _DEBUG_ALBEDO _DEBUG_METALNESS _DEBUG_NORMALS _DEBUG_SMOOTHNESS _DEBUG_OCCLUSION _DEBUG_SHADOWS
 
             #pragma vertex   LitPassVertex
             #pragma fragment DebugPassFragment

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/Subsurface/LightweightSubsurface.shader

             // GPU Instancing
             #pragma multi_compile_instancing
 
-            #pragma multi_compile _ _DEBUG_ALBEDO _DEBUG_METALNESS _DEBUG_NORMALS _DEBUG_SMOOTHNESS _DEBUG_OCCLUSION
+            #pragma multi_compile _ _DEBUG_ALBEDO _DEBUG_METALNESS _DEBUG_NORMALS _DEBUG_SMOOTHNESS _DEBUG_OCCLUSION _DEBUG_SHADOWS
 
             #pragma vertex   LitPassVertex
             #pragma fragment DebugPassFragment