QNX QPA plugin does not provide configurable display selection

Currently in QNX QPA plugin primary display is always configured to be the first in the list QNX provides. It should be configurable what display should be used.

http://code.qt.io/cgit/qt/qtbase.git/tree/src/plugins/platforms/qnx/qqnxintegration.cpp#n438

Issue arises when there is multiple (minimum of two) displays configured in QNX Screen, preferred display is not the first one provided and displays have different resolution. Because then all OpenGL/EGL items are created with first screen properties (resolution mainly) so even when second display is the only one connected there is nothing visible in the display.

Example:

begin display 1
formats = rgba8888, rgbx8888, rgb565, rgb888, yuy2, uyvy
video-mode = 1920 x 1080 @ 60
end display

begin display 2
formats = rgba8888, rgbx8888, rgb565, rgb888, yuy2, uyvy
video-mode = 1920 x 720 @ 60
end display