misc: Adapt consistent import style formatting

Historically the Cloud Hypervisor coding style has been to ensure that
all imports are ordered and placed in a single group. Unfortunately
cargo fmt has no support for ensuring that all imports are in a single
group so if whitespace lines were added as part of the import statements
then they would only be odered correctly in the group.

By adopting "group_imports="StdExternalCrate" we can enforce a style
where imports are placed in at most three groups for std, external
crates and the crate itself. Choosing a style enforceable by the tooling
reduces the reviewer burden.

Signed-off-by: Rob Bradford <rbradford@rivosinc.com>

src/bin/ch-remote.rs

@@ -3,17 +3,18 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
+use std::fmt;
+use std::io::Read;
+use std::marker::PhantomData;
+use std::os::unix::net::UnixStream;
+use std::process;
+
 use api_client::simple_api_command;
 use api_client::simple_api_command_with_fds;
 use api_client::simple_api_full_command;
 use api_client::Error as ApiClientError;
 use clap::{Arg, ArgAction, ArgMatches, Command};
 use option_parser::{ByteSized, ByteSizedParseError};
-use std::fmt;
-use std::io::Read;
-use std::marker::PhantomData;
-use std::os::unix::net::UnixStream;
-use std::process;
 #[cfg(feature = "dbus_api")]
 use zbus::{proxy, zvariant::Optional};