vmm: Introduce console_devices module

Introduce ConsoleInfo struct. This struct will be used to store FDs of
console devices created in pre_create_console_devices and passed to
vm_boot.

Move set_raw_mode, create_pty methods to console_devices.rs to
consolidate console management methods into a single module.

Lastly, copy the logic to create and configure console devices into
pre_create_console_devices method.

Signed-off-by: Praveen K Paladugu <prapal@linux.microsoft.com>

vmm/src/lib.rs

@@ -63,6 +63,7 @@ mod acpi;
 pub mod api;
 mod clone3;
 pub mod config;
+pub mod console_devices;
 #[cfg(all(target_arch = "x86_64", feature = "guest_debug"))]
 mod coredump;
 pub mod cpu;