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/etc.rs

@@ -0,0 +1,54 @@
+use crate::config;
+use crate::APP_LOG_DIR;
+
+// Learn more about Tauri commands at https://tauri.app/v1/guides/features/command
+
+#[tauri::command]
+pub fn get_app_version() -> String {
+    if let Some(res) = config::APP_VERSION {
+        res.to_string()
+    } else {
+        String::from("error")
+    }
+}
+
+#[tauri::command]
+pub fn get_author_name() -> String {
+    if let Some(res) = config::AUTHOR_NAME {
+        res.to_string()
+    } else {
+        String::from("error")
+    }
+}
+
+#[tauri::command]
+pub fn get_repository_link() -> String {
+    if let Some(res) = config::REPOSITORY_LINK {
+        res.to_string()
+    } else {
+        String::from("error")
+    }
+}
+
+#[tauri::command]
+pub fn get_tg_official_link() -> String {
+    if let Some(ver) = config::TG_OFFICIAL_LINK {
+        ver.to_string()
+    } else {
+        String::from("error")
+    }
+}
+
+#[tauri::command]
+pub fn get_feedback_link() -> String {
+    if let Some(res) = config::FEEDBACK_LINK {
+        res.to_string()
+    } else {
+        String::from("error")
+    }
+}
+
+#[tauri::command]
+pub fn get_log_file_path() -> String {
+    format!("{}", APP_LOG_DIR.lock().unwrap())
+}