... and re-use the old QtcProcess::readAllStandard* names for
a QString-returning 'decoded' version.
For now, only use that in 'full Utf8' cases, to stay bug-compatible,
the plan is, however, to employ the QTextCodecs we have already
in the channel buffers. That will be one-by-one, though.
Change-Id: Id209e0671920d4ea4197918e872f441254112d52
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>