Add JSON text renderer (#1086)

* Add JsonText widget to render highlighted JSON

Closes #1051

docs/input/widgets/json.md

@@ -0,0 +1,69 @@
+Title: JSON
+Order: 70
+Description: "Use *ImageSharp* to parse images and render them as Ascii art to the console."
+Reference: T:Spectre.Console.Json.JsonText
+---
+
+To add JSON superpowers to 
+your console application to render JSON text, you will need to install 
+the [Spectre.Console.Json](https://www.nuget.org/packages/Spectre.Console.Json) NuGet package.
+
+```text
+> dotnet add package Spectre.Console.Json
+```
+
+## Loading images
+
+Once you've added the `Spectre.Console.Json` NuGet package, 
+you can start rendering JSON to the console.
+
+```csharp
+using Spectre.Console.Json;
+
+var json = new JsonText(
+    """
+    { 
+        "hello": 32, 
+        "world": { 
+            "foo": 21, 
+            "bar": 255,
+            "baz": [
+                0.32, 0.33e-32,
+                0.42e32, 0.55e+32,
+                {
+                    "hello": "world",
+                    "lol": null
+                }
+            ]
+        } 
+    }
+    """);
+
+AnsiConsole.Write(
+    new Panel(json)
+        .Header("Some JSON in a panel")
+        .Collapse()
+        .RoundedBorder()
+        .BorderColor(Color.Yellow));
+```
+
+### Result
+
+<?# AsciiCast cast="json" /?>
+
+## Styling
+
+All the different JSON parts can be customized to have unique styles.
+
+```csharp
+AnsiConsole.Write(
+    new JsonText(json)
+        .BracesColor(Color.Red)
+        .BracketColor(Color.Green)
+        .ColonColor(Color.Blue)
+        .CommaColor(Color.Red)
+        .StringColor(Color.Green)
+        .NumberColor(Color.Blue)
+        .BooleanColor(Color.Red)
+        .NullColor(Color.Green));
+```