Preparations for the 1.0 release

* Less cluttered solution layout.
* Move examples to a repository of its own.
* Move Roslyn analyzer to a repository of its own.
* Enable central package management.
* Clean up csproj files.
* Add README file to NuGet packages.

src/Extensions/Spectre.Console.Json/JsonTokenReader.cs

@@ -0,0 +1,55 @@
+namespace Spectre.Console.Json;
+
+internal sealed class JsonTokenReader
+{
+    private readonly List<JsonToken> _reader;
+    private readonly int _length;
+
+    public int Position { get; private set; }
+    public bool Eof => Position >= _length;
+
+    public JsonTokenReader(List<JsonToken> tokens)
+    {
+        _reader = tokens;
+        _length = tokens.Count;
+
+        Position = 0;
+    }
+
+    public JsonToken Consume(JsonTokenType type)
+    {
+        var read = Read();
+        if (read == null)
+        {
+            throw new InvalidOperationException("Could not read token");
+        }
+
+        if (read.Type != type)
+        {
+            throw new InvalidOperationException($"Expected '{type}' token, but found '{read.Type}'");
+        }
+
+        return read;
+    }
+
+    public JsonToken? Peek()
+    {
+        if (Eof)
+        {
+            return null;
+        }
+
+        return _reader[Position];
+    }
+
+    public JsonToken? Read()
+    {
+        if (Eof)
+        {
+            return null;
+        }
+
+        Position++;
+        return _reader[Position - 1];
+    }
+}