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/portfolio/document/overlays/mod.rs

@@ -5,6 +5,6 @@ pub mod utility_functions;
 pub mod utility_types;
 
 #[doc(inline)]
-pub use overlays_message::*;
+pub use overlays_message::{OverlaysMessage, OverlaysMessageDiscriminant};
 #[doc(inline)]
-pub use overlays_message_handler::*;
+pub use overlays_message_handler::{OverlaysMessageData, OverlaysMessageHandler};

editor/src/messages/portfolio/document/overlays/overlays_message.rs

@@ -1,10 +1,8 @@
 use super::utility_types::{empty_provider, OverlayProvider};
 use crate::messages::prelude::*;
 
-use serde::{Deserialize, Serialize};
-
 #[impl_message(Message, DocumentMessage, Overlays)]
-#[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
+#[derive(PartialEq, Clone, Debug, serde::Serialize, serde::Deserialize)]
 pub enum OverlaysMessage {
 	Draw,
 

editor/src/messages/portfolio/document/overlays/overlays_message_handler.rs

@@ -1,6 +1,11 @@
 use super::utility_types::OverlayProvider;
 use crate::messages::prelude::*;
 
+pub struct OverlaysMessageData<'a> {
+	pub overlays_visible: bool,
+	pub ipp: &'a InputPreprocessorMessageHandler,
+}
+
 #[derive(Debug, Clone, Default)]
 pub struct OverlaysMessageHandler {
 	pub overlay_providers: HashSet<OverlayProvider>,
@@ -8,8 +13,10 @@ pub struct OverlaysMessageHandler {
 	context: Option<web_sys::CanvasRenderingContext2d>,
 }
 
-impl MessageHandler<OverlaysMessage, (bool, &InputPreprocessorMessageHandler)> for OverlaysMessageHandler {
-	fn process_message(&mut self, message: OverlaysMessage, responses: &mut VecDeque<Message>, (overlays_visible, ipp): (bool, &InputPreprocessorMessageHandler)) {
+impl MessageHandler<OverlaysMessage, OverlaysMessageData<'_>> for OverlaysMessageHandler {
+	fn process_message(&mut self, message: OverlaysMessage, responses: &mut VecDeque<Message>, data: OverlaysMessageData) {
+		let OverlaysMessageData { overlays_visible, ipp } = data;
+
 		match message {
 			#[cfg(target_arch = "wasm32")]
 			OverlaysMessage::Draw => {