Prohibit reflection with Activator.CreateInstance

[SteveDunn]

The purpose of this change is to phohibit creation using Activator.CreateInstance.

Creating Value Objects with Reflection evades the validation mechanism, allowing invalid Value Objects to be live in the domain of the application.

For instance, with this Value Object:

[ValueObject]
public partical struct CustomerId {{ }}

It disallows this:

// result in error VOG025: Type 'CustomerId' cannot be constructed via Reflection as it 
var c = Activator.CreateInstance<CustomerId>(); is prohibited.

and...

// result in error VOG025: Type 'CustomerId' cannot be constructed via Reflection as it 
var c = (CustomerId)Activator.CreateInstance();