build system cleanups

build system cleanups

- load(qt_module) => load(qt_build_config)
- remove:
  - CONFIG+=module (obsolete)
  - setup of PKGCONFIG* variables (automated now)
  - code relating to module version headers (automated now)
  - %mastercontent assignment (automated now)
  - QT_BUILD_*_LIB defines (automated now)
  - pointless QPRO_PWD assignments
  - pointless and commented out include and depend paths
  - qmake -project boilerplate

Change-Id: Ib2d80a375e88bae1b50a22a274374b7e2cc2a86c
Reviewed-by: Alan Alpert <alan.alpert@nokia.com>