Qt Remote Objects: Support enums in namespaces in .rep files

Currently, ENUM{} can only be applied inside a class{}. Consequently, the enum is not accessible to other Sources and Replicas; the following .rep file produces a compilation error:

class Aaa
{
    ENUM Color{Blue=0, Red=1};
    PROP(Color colorOfA=Blue);
};

class Bbb
{
    PROP(Aaa::Color colorOfB=Aaa::Red); // error: C2653: 'Aaa': is not a class or namespace name
};

This is because the generated C++ files contain AaaSource::Color and AaaReplica::Color.

Suggestion

Let REPC handle namespaces (and enums in namespaces). Take advantage of the existing Q_NAMESPACE and Q_ENUM_NS() macros (https://doc.qt.io/qt-6/qobject.html#Q_ENUM_NS ) to support constructs like this:

namespace NS
{
    ENUM Color{Blue=0, Red=1};
}

class Aaa
{
    PROP(NS::Color colorOfA=NS::Blue);
};

class Bbb
{
    PROP(NS::Color colorOfB=NS::Red);
};

This should be easy to add, since the namespace can have the same name on both the Source and Replica side (like a POD/Q_GADGET)