race condition when starting server prevents next key release event

[digitalsignalperson]

As described in this comment in #45, when pressing the Enter key to start rkvm in the terminal, the key release event may be eaten by rkvm. The effect can be weirdness with different input events and spamming of newlines in the terminal until the Enter key is pressed again to provide the missing release event.

[slartibart70]

This also happens when starting the service on the commandline with systemctl. Some automatically added newlines are pushed to the open terminal

[NamPNQ]

From suggestion of @htrefil, I just do this for the fix

https://github.com/htrefil/rkvm/blob/e29d9895695d74d50658858fd83d9c875f5673ef/rkvm-server/src/main.rs#L28

 #[tokio::main]
 async fn main() -> ExitCode {
+    time::sleep(Duration::from_millis(100)).await;
     let filter = EnvFilter::builder()