fix: make io_uring_queue_init_mem usable from Python (#30)

[meshya]

• class.zig — add Param.__new__(flags) / __del__.
• uring.zig — rewrite as internal _io_uring_queue_init_mem
• root.zig — register _io_uring_queue_init_mem.
• uring.py — Python layer exposing the public io_uring_queue_init_mem.
• init.py — import from uring.py.
• conftest.py — parametrize the ring initial over both io_uring_queue_init and io_uring_queue_init_mem.
• init_exit_test.py — dedicated test_io_uring_init_mem.
• send_recv_test.py — test io_uring_prep_recv & io_uring_prep_send.

[YoSTEALTH]

First of all thank you very much for writing this PR.

• Would you mind uploading it to dev branch, so I can download and test it. After I should be able to merge it to "main" (I think!)
• It would be better to keep send_recv_test.py separate as you already submitted it before, just reopen that PR (maybe move it to dev as well).

Sorry for really slow reply I am mostly away from coding over the summer time.

[meshya]

Thanks for your reply.
PR rebaced.