The pipeline setting patch is removed

We did the patch for Qt base to make it possible to set pipeline value for QNX.

It is not a part of 5.15.2 release, but the next one so we need to add the patch to the documentation (the patch from 5.15 is enclosed)

Also, there is added the new environment variable to the QSR adaptation:

QSR_QNX_SCREEN_PIPELINE

That can be used to set the pipeline value for the telltale application.