Add support for building several modules from one git repository

We need to support building several modules from same git repository. At the moment that isn't possible & that's way we need to do & maintain huge hacks in packaging side. Doing that will be impossible now when this kind of situations come in several repositories (at the moment that has been only in qtlocation.git where has been qtlocation and qtpositioning modules).

Knowns plans are:
qtwebengine.git:
-qtwebengine
-qtpdf

qtwayland.git:
-wayland client
-wayland server

And maybe with Qt6 there will be several more.

And all above are coming in Qt 5.14 schedule