Qt Toolkit Lands IO_uring Abstraction

The newest feature to land in the cross-platform Qt toolkit is QIORing as an abstraction for Linux's IO_uring interface. This QIORing may also end up supporting Microsoft's Windows IORing implementation as well.

QIORing is now merged to the Qt toolkit for abstracting IO_uring Linux usage from this Qt interface:

"Introduce QIORing to abstract io_uring on Linux

Somewhat low level code, intended as a low level abstraction.

The QIORing interface would also be used for Windows' IORing, developed at the same time as the io_uring version. There is some shared code and helper functions, but a lot of the code in some way touch the platform specifics, so without yet more abstractions quite some code is left as unique."

The code landed via this merge. The code had been worked on over the past several months by Mårten Nordheim.