VisibleMembers should allow defining the surface of a subtree

[realvizu]

At the moment, with Allowed/VisibleMembers you can define the surface of only a single namespace. (The To namespace can not be a subtree.)
Eg.

    <Allowed From="Codartis.NsDepCop.Core.Factory" To="Codartis.NsDepCop.Core.Implementation.Analysis.NRefactory">
        <VisibleMembers>
            <Type Name="NRefactoryDependencyAnalyzer" />
        </VisibleMembers>
    </Allowed>

It should be allowed to define the surface of a subtree as well.
Eg.

    <Allowed From="Codartis.NsDepCop.Core.Factory" To="Codartis.NsDepCop.Core.Implementation.*">
        <VisibleMembers>
            <Type RelativeName="Analysis.ConfiguredAnalyzer" />
            <Type RelativeName="Analysis.IAnalyzerFactory" />
            <Type RelativeName="Analysis.NRefactory.NRefactoryDependencyAnalyzer" />
            <Type RelativeName="Analysis.Roslyn.RoslynDependencyAnalyzer" />
            <Type RelativeName="Config.XmlFileConfigProvider" />
        </VisibleMembers>
    </Allowed>

In this case the Type elements must describe not only the type name but also its relative namespace path.

The same should apply to VisibleMembers elements with the OfNamespace attribute.