DomainResponse should expose a type safe payload

[guilhermeluizsp]

DomainResponse has a PayLoad property that represents the actual value of a business operation. Currently, this property is of type JToken, making it awkward to use as we always have to call the JToken.ToObject method.

https://github.com/Avanade/Liquid-Application-Framework/blob/93f7874f2ead13d3602cc39fc1e9355206217f57/src/Liquid.Domain/Base/Domain/DomainResponse.cs#L25-L28

In my opinion, DomainResponse should have two versions: A base one, without the payload, and a second one with a type safe payload property:

//extra code removed for readability reasons
public class DomainResponse
{
    public JToken Critics { get; set; }
}

public class DomainResponse<TPayload> : DomainResponse
{
    public TPayload Payload { get; set; }
}

Why

• Not every business operation returns a value. Some of them just indicates if everything went right (e.g "Successfully saved")
• Relying on type safety is always beneficial as we can solve things at compile time, and also makes the code clearer to the developers

What to consider

• Since this would be a breaking change, maybe we should introduce a new class, considering that DomainResponse already has a couple of issues (#57, #54, #35)