refactor: make icon overrides bar-level and apply to focused module

src/config/mod.rs

@@ -290,6 +290,12 @@ pub struct BarConfig {
     /// **Default**: `null`
     pub icon_theme: Option<String>,
 
+    /// Map of app IDs (or classes) to icon names,
+    /// overriding the app's default icon.
+    ///
+    /// **Default**; `null`
+    pub icon_overrides: Option<HashMap<String, String>>,
+
     /// An array of modules to append to the start of the bar.
     /// Depending on the orientation, this is either the top of the left edge.
     ///
@@ -338,6 +344,7 @@ impl Default for BarConfig {
             start_hidden: None,
             autohide: None,
             icon_theme: None,
+            icon_overrides: None,
             start: Some(vec![ModuleConfig::Label(
                 LabelModule::new("ℹ️ Using default config".to_string()).into(),
             )]),