Integrate Cake.Json

The [Cake.Json](https://github.com/cake-contrib/Cake.Json) addin provides some aliases which are wrappers around JSON.NET. Having this functionality in an addin is tricky since Newtonsoft.Json is bundled by Cake itself. As we already have this dependency we could also provide the aliases as part of Cake.Common without all the dependency and compatibility issues which are there if the code is part of an addin.

Start by reviewing the Cake.Json addin linked in the issue and the Cake.Common area of the Cake repository to understand the aliases and dependency setup. Compare how Newtonsoft.Json is already bundled by Cake. Done means the relevant JSON aliases are provided by Cake.Common without the addin's dependency or compatibility issues.

Written by the indexing model from the issue text.