[$] Process creation in io_uring

Back in 2022, Josh Triplett presented a
plan to implement a 'spawn new process' functionality in the io_uring
subsystem. There was a fair amount of interest at the time, but developers
got distracted, and the work did not progress. Now, Gabriel Krisman
Bertazi has returned with a patch series
updating and improving Triplett's work. While interest in this
functionality remains, it may still take some time before it is ready for
merging into the mainline.