This matters for libraries in the same repository as the application that
also have an AAR that needs to be integrated, as well as QML plugins. For
this to work we need to consider the build directory as a search prefix,
and produce the exact directory layout there that androiddeployqt expects.

For libraries this is then almost transparent for the application build
system, the only thing that needs to be taken care of manually is putting
the corresponding -android-dependencies.xml file into the right place in
the build dir as well. A macro wrapping that might be an option to
centralize that logic here as well in the future.

For QML plugins this is transparent if you have them set up to work without
installation already anyway, otherwise that setup has to be done for this
to work.

Example: pim/itinerary!28

knotifications!12 would
presumably also need this (not tested yet).