Also make the tool package depend on all tool packages that correspond
to the qt module dependencies.
So find_package(Qt5Widgets) implicitly calls find_package(Qt5WidgetTools).
And find_package(Qt5WidgetsTools) will call find_package for
Qt5GuiTools, and Qt5CoreTools.
This enhances the user experience, so that in modules like qtsvg, you
don't have to specify both find_package(Qt5Widgets) and
find_package(Qt5WidgetsTools), but only the former.
Or when cross building, you only need to specify Qt5WidgetTools, to get
both Core and Gui tools.
Change-Id: Ib1c5173a5b97584a52e144c22e38e90a712f727a
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
