Support @Embeddable bindings in CTEs

[Mobe91]

Currently we only support the binding of simple attributes in CTEs. In some cases it would be handy to be able to bind e.g. embedded ids like:

.bind("id.a").select(...)
.bind("id.b").select(...)

[beikov]

This is roughly about the same: #300

I will bind expression to the target columns instead of on attribute level to make this and also the other usage as shown in #300 possible.