Doc: Edited Qt Positioning example pages

-added information on how to run the example
 (using an included file in qtbase/doc/global)
-section changes and linked to module landing page.
-assigning default thumbnail to an example.
-updated copyright year in touched files.

Task-number: QTBUG-33597
Change-Id: I6e78c3016d3f51dd99466ee37eff9632eb050d84
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>