[OE-core] [dora] Cherry-pick Qt fixes

[Jonathan Liu]

Hi Robert,

I propose we cherry-pick the following Qt fixes from master to dora branch:
-qt4: add upstream QTBUG-31579 patch for QPainter regression 
[OE-Core/a5afc67cbfc32beb3be10392bf9788cfc3610ab1]
-nativesdk-qt4-tools: create qt.conf file 
[OE-Core/23f88695683a8e428375a8ccb6be935347a8768c]
-meta-toolchain-qt: put QT_CONF_PATH in environment script 
[OE-Core/fffa4c37c49b169f663d28612b9251819cef9577]
-qt4: add upstream QTBUG-34218/QTBUG-34234 misaligned selection patch 
[OE-Core/3af8f2e0697a9523d3b505ba4c48eca35f6de3a9]

Regards,
Jonathan