Allow contract-less composition request handlers to inherit from a base class

[mauroservienti]

Similar to ASP.Net controllers, if a contract-less composition request handler inherits from a base/abstract CompositionHandler class, it'll get access to some base class properties, for example, an HttpRequest Request{ get; } property that allows accessing the current HTTP request without the need of the HttpContextAccessor.

[mauroservienti]

Or detect property patters and inject values at runtime