Add rustfmt.toml for explicit styling (#348)

* Propose an explicit .rustfnt.toml
Use 2024 style, 4 spaces for tabs and epand the default width a tad

* Auto-format the existing code with new rules

lan-mouse-gtk/src/client_row.rs

@@ -4,7 +4,7 @@ use adw::prelude::*;
 use adw::subclass::prelude::*;
 use gtk::glib::{self, Object};
 
-use lan_mouse_ipc::{Position, DEFAULT_PORT};
+use lan_mouse_ipc::{DEFAULT_PORT, Position};
 
 use super::ClientObject;