Remove bscreensaver-dialog-gtk4

I don't think it's even possible to use gtk4 to build a dialog, as gtk4
has dropped GtkPlug/GtkSocket and doesn't support embedding anymore.
They also don't seem to give access to enough internals so I can build
it myself.

Cargo.toml

@@ -5,7 +5,6 @@ members = [
     "locker",
     "dbus-service",
     "dialog-gtk3",
-#    "dialog-gtk4",
 #    "dialog-iced",
     "util",
     "systemd",

dialog-gtk4/Cargo.toml

@@ -1,9 +0,0 @@
-[package]
-name = "bscreensaver-dialog-gtk4"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
-gtk = { version = "0.4", package = "gtk4", features = ["v4_6"]}
-gdk-x11 = { version = "0.4", package = "gdk4-x11", features = ["v4_4", "xlib"]}
-x11 = "2.19"

dialog-gtk4/src/main.rs

@@ -1,43 +0,0 @@
-use gdk_x11::{X11Surface, X11Display};
-use gtk::{prelude::*, Application, ApplicationWindow, Label};
-use std::process::exit;
-
-fn main() {
-    let app = Application::builder()
-        .application_id("org.spurint.bscreensaver.dialog-gtk4")
-        .build();
-    app.connect_activate(build_ui);
-
-    app.run();
-}
-
-fn build_ui(app: &Application) {
-    let titlebar = Label::builder()
-        .label("Unlock Screen")
-        .halign(gtk::Align::Center)
-        .single_line_mode(true)
-        .build();
-    titlebar.show();
-
-    let window = ApplicationWindow::builder()
-        .application(app)
-        .titlebar(&titlebar)
-        .modal(true)
-        .decorated(false)
-        .build();
-    window.realize();
-
-    let surface = unsafe { window.surface().unsafe_cast::<X11Surface>() };
-    let xid = surface.xid();
-    if xid == 0 {
-        eprintln!("Lock dialog has no XID");
-        exit(1);
-    }
-    println!("{}", surface.xid());
-
-    let mut buf = String::new();
-    let stdin = std::io::stdin();
-    stdin.read_line(&mut buf).unwrap();
-
-    window.present();
-}