Added front-matter for samples (dotnet#805)

Author: luisquintanilla

samples/modelbuilder/ImageClassification_Azure_LandUse/LandUseAPI/Controllers/ClassificationController.cs

@@ -40,7 +40,7 @@ public async Task<string> ClassifyImage([FromBody] Dictionary<string, string> in
 
             lock (_predictionEngineLock)
             {
-                // Use Prediction to classify image
+                // Use PredictionEngine to classify image
                 ModelOutput output = _predictionEngine.Predict(new ModelInput { ImageSource = imagePath });
                 prediction = output.Prediction;
             }

samples/modelbuilder/ImageClassification_Azure_LandUse/LandUseAPI/Controllers/WeatherForecastController.cs

@@ -1,3 +1,19 @@
+---
+page_type: sample
+name: "Train a deep learning image classification model in Azure with ML.NET Model Builder"
+description: "Use ML.NET Model Builder to train a deep learning image classification model in Azure"
+urlFragment: "mlnet-image-classification-azure-model-builder"
+languages:
+- csharp
+products:
+- dotnet
+- dotnet-core
+- aspnet-core
+- vs
+- windows
+- windows-uwp
+---
+
 # Image Classification in Azure with Model Builder
 
 | ML.NET version | Status                        | App Type    | Data type | Scenario            | ML Task                   | Algorithms                  |