First version of QtCreator IDE integration :
'make qtcreator-ide-integration' generates .pro and .pro.user files for each subfolder of LibreOffice.
It also creates a 'lo.pro' meta project that list all other .pro files.
Developers can use use QtCreator to edit, compile and debug LibreOffice.

Change-Id: Ib05d8c36a7ca055ecd7a4db5776f4c28bf05676c
Reviewed-on: https://gerrit.libreoffice.org/15804Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>