✨ feat(cli): add list subcommand

- Implement list subcommand to display Gmail messages
- Use google_gmail1 crate to interact with Gmail API

src/list_cli.rs

@@ -0,0 +1,32 @@
+use clap::Parser;
+use google_gmail1::{
+    Error, Gmail, hyper_rustls::HttpsConnector, hyper_util::client::legacy::connect::HttpConnector,
+};
+
+/// Command line options for the list subcommand
+#[derive(Debug, Parser)]
+pub struct ListCli {}
+
+impl ListCli {
+    pub(crate) async fn run(&self, hub: Gmail<HttpsConnector<HttpConnector>>) {
+        let result = hub.users().messages_list("me").doit().await;
+
+        match result {
+            Err(e) => match e {
+                // The Error enum provides details about what exactly happened.
+                // You can also just use its `Debug`, `Display` or `Error` traits
+                Error::HttpError(_)
+                | Error::Io(_)
+                | Error::MissingAPIKey
+                | Error::MissingToken(_)
+                | Error::Cancelled
+                | Error::UploadSizeLimitExceeded(_, _)
+                | Error::Failure(_)
+                | Error::BadRequest(_)
+                | Error::FieldClash(_)
+                | Error::JsonDecodeError(_, _) => println!("{e}"),
+            },
+            Ok(res) => println!("Success: {res:?}"),
+        }
+    }
+}