[oe] [meta-qt5][RFC] Initial recipes for QtWebEngine

[Simon Busch]

Hey everyone,

I spent some time last weekend to get finally a first version of qtwebengine building
inside OE. The current state builds without any problems and is also usable to some
degree at runtime. Sadly I didn't had much time to do some extensive testing with it
on a target device so I first submit the two changes needed as RFC. I hope that helps
some people to get also started with QtWebEngine in OE until we have a fully working
and verified version ready.

regards,
Simon