Inspired by dotnet show (#386)

* Changed the order of the projects, Web first to infer as startup.

* Added encapsulated JSON serialization - and moved to System.Text.Json

* Refactored a few minor updates out

Co-authored-by: Eric Fleming <eric-fleming18@hotmail.com>

src/ApplicationCore/ApplicationCore.csproj

@@ -9,6 +9,7 @@
 		<PackageReference Include="Ardalis.GuardClauses" Version="1.5.0" />
 		<PackageReference Include="Ardalis.Specification" Version="3.0.0" />
 		<PackageReference Include="System.Security.Claims" Version="4.3.0" />
+		<PackageReference Include="System.Text.Json" Version="4.7.2" />
 	</ItemGroup>
 
 </Project>

src/ApplicationCore/Extensions/JsonExtensions.cs

@@ -0,0 +1,18 @@
+using System.Text.Json;
+
+namespace Microsoft.eShopWeb
+{
+    public static class JsonExtensions
+    {
+        private static readonly JsonSerializerOptions _jsonOptions = new JsonSerializerOptions
+        {
+            PropertyNameCaseInsensitive = true
+        };
+
+        public static T FromJson<T>(this string json) =>
+            JsonSerializer.Deserialize<T>(json, _jsonOptions);
+
+        public static string ToJson<T>(this T obj) =>
+            JsonSerializer.Serialize<T>(obj, _jsonOptions);
+    }
+}