Code cleanup and refactoring to enhance consistency (#1695)

- Move message handler payload data into structs
- Organize the file structure used by `editor/src/messages/portfolio/document` `/node_graph` and `/graph_operation`
- Make derive attributes use `serde::Serialize, serde::Deserialize` consistently instead of `use serde::{Deserialize, Serialize};` imports
- Various other code cleanup and refactoring

editor/src/messages/dialog/preferences_dialog/mod.rs

@@ -4,4 +4,4 @@ mod preferences_dialog_message_handler;
 #[doc(inline)]
 pub use preferences_dialog_message::{PreferencesDialogMessage, PreferencesDialogMessageDiscriminant};
 #[doc(inline)]
-pub use preferences_dialog_message_handler::PreferencesDialogMessageHandler;
+pub use preferences_dialog_message_handler::{PreferencesDialogMessageData, PreferencesDialogMessageHandler};

editor/src/messages/dialog/preferences_dialog/preferences_dialog_message.rs

@@ -1,9 +1,7 @@
 use crate::messages::prelude::*;
 
-use serde::{Deserialize, Serialize};
-
 #[impl_message(Message, DialogMessage, PreferencesDialog)]
-#[derive(Eq, PartialEq, Clone, Debug, Serialize, Deserialize)]
+#[derive(Eq, PartialEq, Clone, Debug, serde::Serialize, serde::Deserialize)]
 pub enum PreferencesDialogMessage {
 	Confirm,
 }

editor/src/messages/dialog/preferences_dialog/preferences_dialog_message_handler.rs

@@ -1,12 +1,18 @@
 use crate::messages::layout::utility_types::widget_prelude::*;
 use crate::messages::prelude::*;
 
+pub struct PreferencesDialogMessageData<'a> {
+	pub preferences: &'a PreferencesMessageHandler,
+}
+
 /// A dialog to allow users to customize Graphite editor options
 #[derive(Debug, Clone, Default)]
 pub struct PreferencesDialogMessageHandler {}
 
-impl MessageHandler<PreferencesDialogMessage, &PreferencesMessageHandler> for PreferencesDialogMessageHandler {
-	fn process_message(&mut self, message: PreferencesDialogMessage, responses: &mut VecDeque<Message>, preferences: &PreferencesMessageHandler) {
+impl MessageHandler<PreferencesDialogMessage, PreferencesDialogMessageData<'_>> for PreferencesDialogMessageHandler {
+	fn process_message(&mut self, message: PreferencesDialogMessage, responses: &mut VecDeque<Message>, data: PreferencesDialogMessageData) {
+		let PreferencesDialogMessageData { preferences } = data;
+
 		match message {
 			PreferencesDialogMessage::Confirm => {}
 		}