net: socket: syscall for socketpair(2)

Working:

* non-blocking reads / writes
* blocking reads / writes
* send(2) / recv(2) / sendto(2) / recvfrom(2) / sendmsg(2)
* select(2)
* poll(2)

Fixes #24366

Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>