Add a per Tab config

A tab config is useful for allowing users to show hidden files, sorting
by different metrics such as size or MIME type, as well as providing a
way to implement some of the todos such as configurable icon sizes for
views.

src/config.rs

@@ -28,12 +28,33 @@ impl AppTheme {
 #[derive(Clone, CosmicConfigEntry, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct Config {
     pub app_theme: AppTheme,
+    pub tab: Tab,
 }
 
 impl Default for Config {
     fn default() -> Self {
         Self {
             app_theme: AppTheme::System,
+            tab: Tab::default(),
         }
     }
 }
+
+/// Per tab config
+#[derive(Clone, Debug, Eq, PartialEq, CosmicConfigEntry, Deserialize, Serialize)]
+pub struct Tab {
+    /// Show hidden files
+    pub show_hidden: bool,
+    // TODO: Other possible options
+    // pub sort_by: fn(&PathBuf, &PathBuf) -> Ordering,
+    // Icon handle sizes
+    // icon_size_dialog: u16,
+    // icon_size_list: u16,
+    // icon_size_grid: u16,
+}
+
+impl Default for Tab {
+    fn default() -> Self {
+        Self { show_hidden: false }
+    }
+}