QGeoCoordinate QDebug stream operator precision insufficient

The QDebug stream operator for QGeoCoordinate does not specify a floating point precision for the text stream. As a result coordinates are defaulted to printing 6 digits which often truncates them before useful coordinates are expressed.

Additionally some users may not care, but for others the inadvertent logging of coordinates could be considered a security risk. I'd like to propose adding a pair of static methods to QGeoCoordinate that allow getting/setting the default QDebug stream operator real number precision. This will allow flexibility to deal with both cases.