refactor: move most of the horrible add_module macro content into proper functions

src/modules/custom.rs

@@ -21,7 +21,7 @@ pub struct CustomModule {
     popup: Option<Vec<Widget>>,
 
     #[serde(flatten)]
-    pub common: CommonConfig,
+    pub common: Option<CommonConfig>,
 }
 
 /// Attempts to parse an `Orientation` from `String`
@@ -168,6 +168,10 @@ impl Module<gtk::Box> for CustomModule {
     type SendMessage = ();
     type ReceiveMessage = ExecEvent;
 
+    fn name() -> &'static str {
+        "custom"
+    }
+
     fn spawn_controller(
         &self,
         _info: &ModuleInfo,