App architecture modifications.

Now GUI and the app itself is divided into two different binaries.
The app also provides system tray icon.
Whereas the GUI can be used to configure the app.

gui/src-tauri/src/tauri_commands/fs.rs

@@ -0,0 +1,47 @@
+use std::process::Command;
+
+// taken from https://github.com/tauri-apps/tauri/issues/4062#issuecomment-1338048169
+#[tauri::command]
+pub fn show_in_folder(path: String) {
+  #[cfg(target_os = "windows")]
+  {
+    Command::new("explorer")
+        .args(["/select,", &path]) // The comma after select is not a typo
+        .spawn()
+        .unwrap();
+  }
+
+  #[cfg(target_os = "linux")]
+  {
+    if path.contains(",") {
+      // see https://gitlab.freedesktop.org/dbus/dbus/-/issues/76
+      let new_path = match metadata(&path).unwrap().is_dir() {
+        true => path,
+        false => {
+          let mut path2 = PathBuf::from(path);
+          path2.pop();
+          path2.into_os_string().into_string().unwrap()
+        }
+      };
+      Command::new("xdg-open")
+          .arg(&new_path)
+          .spawn()
+          .unwrap();
+    } else {
+      Command::new("dbus-send")
+          .args(["--session", "--dest=org.freedesktop.FileManager1", "--type=method_call",
+                "/org/freedesktop/FileManager1", "org.freedesktop.FileManager1.ShowItems",
+                format!("array:string:\"file://{path}\"").as_str(), "string:\"\""])
+          .spawn()
+          .unwrap();
+    }
+  }
+
+  #[cfg(target_os = "macos")]
+  {
+    Command::new("open")
+        .args(["-R", &path])
+        .spawn()
+        .unwrap();
+  }
+}