[Development] New maintainers

[Knoll Lars]

Hi,

I'd like to nominate a couple of new maintainers for some parts of Qt currently lacking a maintainer. 

For the kernel subdirectory in Qt Widgets, I'd like to nominate Samuel Roedal. He's been working a lot with the QPA infrastructure and implemented most of the QWidget/QWindow split.

For styles, I had already nominated Jens Bache-Wiig some days ago.

For the rest of Qt Widgets Marc Mutz has volunteered. I'm really happy to see him step up to this and support the nomination. But as the area is rather large, I would longer term be happier if we have separate maintainers for QGraphicsView+related classes and the remaining widgets and dialogs.

For accessibility (across all modules) I'd like to nominate Frederik Gladhorn. He's been working a lot with this area over the last years.

With these people, we should at least have a maintainer again for pretty much every piece in qtbase.

Cheers,
Lars