Layout system implementation and applied to tool options bar (#499)

* initial layout system with tool options

* cargo fmt

* cargo fmt again

* document bar defined on the backend

* cargo fmt

* removed RC<RefCell>

* cargo fmt

* - fix increment behavior
- removed hashmap from layout message handler
- removed no op message from layoutMessage

* cargo fmt

* only send documentBar when zoom or rotation is updated

* ctrl-0 changes zoom properly

* Code review changes

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/layout/layout_message.rs

@@ -0,0 +1,25 @@
+use super::widgets::WidgetLayout;
+use crate::message_prelude::*;
+
+use serde::{Deserialize, Serialize};
+
+#[remain::sorted]
+#[impl_message(Message, Layout)]
+#[derive(PartialEq, Clone, Deserialize, Serialize, Debug)]
+pub enum LayoutMessage {
+	SendLayout { layout: WidgetLayout, layout_target: LayoutTarget },
+	UpdateLayout { layout_target: LayoutTarget, widget_id: u64, value: serde_json::Value },
+}
+
+#[remain::sorted]
+#[derive(PartialEq, Clone, Deserialize, Serialize, Debug, Hash, Eq, Copy)]
+#[repr(u8)]
+pub enum LayoutTarget {
+	DocumentBar,
+	ToolOptions,
+
+	// KEEP THIS ENUM LAST
+	// This is a marker that is used to define an array that is used to hold widgets
+	#[remain::unsorted]
+	LayoutTargetLength,
+}