Doc: Merged two pages titled "Qt Quick QML Types".

-kept the \qmlmodule page.
-there are two pages with the same titles and it is difficult
 to discern between the two.
-the grouping is lost, but those can be restored in either the use case
 or concept topic pages.
-modified landing page and other pages which link to the unmerged
 document.

Change-Id: I58468c22f0621506e477f30ae2411a382d57b982
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>