use webkit as a fallback for the bundles
after the port to qtwebkit, bundling it with pyinstaller turned out to be a bit more complicated:
- it produces more heavy bundles
- it has some instabilities (although there's a work in progress in pyinstaller that seems to solve many of the problems).
I tried with a docker image in which I compiled a minimal version of qt5 and pyqt5. however, pyqt5 seems to impose cross-module dependencies (qtwebkit depends on qtnetwork, with ssl, qprintsupport and some more. it seems also imposible to disable opengl support in the pyqt5 bindings).
after managing to compile all the pyqt5 modules that we need (and against the updated fork of webkit: https://github.com/annulen/webkit/wiki - as qutebrowser is doing), I got some segfaults when running the produced bundle.
all in all, I think it's not worth the hassle right now, and implementing a fallback to qt5-webkit is good enough for getting bundles working again.