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/export_dialog/export_dialog_message.rs

@@ -1,10 +1,8 @@
 use crate::messages::frontend::utility_types::{ExportBounds, FileType};
 use crate::messages::prelude::*;
 
-use serde::{Deserialize, Serialize};
-
 #[impl_message(Message, DialogMessage, ExportDialog)]
-#[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
+#[derive(PartialEq, Clone, Debug, serde::Serialize, serde::Deserialize)]
 pub enum ExportDialogMessage {
 	FileType(FileType),
 	ScaleFactor(f64),

editor/src/messages/dialog/export_dialog/export_dialog_message_handler.rs

@@ -3,6 +3,10 @@ use crate::messages::layout::utility_types::widget_prelude::*;
 use crate::messages::portfolio::document::utility_types::document_metadata::LayerNodeIdentifier;
 use crate::messages::prelude::*;
 
+pub struct ExportDialogMessageData<'a> {
+	pub portfolio: &'a PortfolioMessageHandler,
+}
+
 /// A dialog to allow users to customize their file export.
 #[derive(Debug, Clone, Default)]
 pub struct ExportDialogMessageHandler {
@@ -14,8 +18,10 @@ pub struct ExportDialogMessageHandler {
 	pub has_selection: bool,
 }
 
-impl MessageHandler<ExportDialogMessage, &PortfolioMessageHandler> for ExportDialogMessageHandler {
-	fn process_message(&mut self, message: ExportDialogMessage, responses: &mut VecDeque<Message>, portfolio: &PortfolioMessageHandler) {
+impl MessageHandler<ExportDialogMessage, ExportDialogMessageData<'_>> for ExportDialogMessageHandler {
+	fn process_message(&mut self, message: ExportDialogMessage, responses: &mut VecDeque<Message>, data: ExportDialogMessageData) {
+		let ExportDialogMessageData { portfolio } = data;
+
 		match message {
 			ExportDialogMessage::FileType(export_type) => self.file_type = export_type,
 			ExportDialogMessage::ScaleFactor(factor) => self.scale_factor = factor,

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

@@ -4,4 +4,4 @@ mod export_dialog_message_handler;
 #[doc(inline)]
 pub use export_dialog_message::{ExportDialogMessage, ExportDialogMessageDiscriminant};
 #[doc(inline)]
-pub use export_dialog_message_handler::ExportDialogMessageHandler;
+pub use export_dialog_message_handler::{ExportDialogMessageData, ExportDialogMessageHandler};