Add @Unwraps from Seam Solder

@Unwraps allows for an essentially stateless scope for producer methods and fields.

At injection time a dependent scoped proxy is injected into the injection point. When a methods is invoked on this proxy it calls the corresponding @Unwraps methods to get the instance to invoke the method on.

Because the proxy is @Dependent scoped, the @Unwraps method can inject the corresponding InjectionPoint.