Support additional interfaces when mock

[scott-xu]

Hi @remogloor , This PR is to implement additional interfaces when mock. The use case is as below. Can you please help have a review?

[Fact]
public void ToMockCanBeUsedToAddAdditionalInterfaces()
{
    using (var kernel = this.CreateKernel())
    {
        kernel.Bind<IDummyService>().ToMock(typeof(IDummyService2));

        var mock = kernel.Get<IDummyService>();

        mock.Should().BeAssignableTo<IDummyService2>();
    }
}

[scott-xu]

Since there's no public API change nor any UT failure, I'd merge it for now.