Replace mio-named-pipes with mio 0.7.2

[alvinhochun]

Windows named pipe is now part of mio 0.7: tokio-rs/mio#1351

[Xanewok]

That's currently blocked on tokio-rs/tokio#3118, because Tokio removed its PollEvented struct from the 1.0 public API - it's great from the stability guarantee PoV but unfortunately it prevents us from upgrading mio::windows::NamedPipe to something that implements Async* traits.

The alternative is to reimplement PollEvented-like facility here but that seems like a big cost which may not outweight its benefits for now.

[rustdesk]

I use named_pipe in tokio v1, but some API change to parity-tokio-ipc. https://github.com/rustdesk/rustdesk/blob/master/libs/parity-tokio-ipc/src/win.rs