Reorganize file layout

Moves satellite to be the root package, also allowing it to be built
by default.

src/main.rs

@@ -0,0 +1,24 @@
+fn main() {
+    pretty_env_logger::formatted_timed_builder()
+        .filter_level(log::LevelFilter::Info)
+        .parse_default_env()
+        .init();
+    xwayland_satellite::main(RealData(get_display()));
+}
+
+#[repr(transparent)]
+struct RealData(Option<String>);
+impl xwayland_satellite::RunData for RealData {
+    fn display(&self) -> Option<&str> {
+        self.0.as_deref()
+    }
+}
+
+fn get_display() -> Option<String> {
+    let mut args: Vec<_> = std::env::args().collect();
+    if args.len() > 2 {
+        panic!("Unexpected arguments: {:?}", &args[2..]);
+    }
+
+    (args.len() == 2).then(|| args.swap_remove(1))
+}