Detecting system wordsize (64/32 bit) from installer.qs script

Installer miss function to detect system wordsize from script. Some applications need to check it for installing correct versions of external binaries.

Could be just wrapper api for QSysInfo::WordSize in Component or PackageManagerCore API class.

Q_INVOKABLE int systemWordSize();

#include <QSysInfo>
int PackageManagerCore::systemWordSize() const
{
return QSysInfo::WordSize;
}