Add support for persistent storage of panel layouts, sizes, and active tabs (#4017)

* Add persistence to panel layouts

* Fix and persist the Window > Focus Document mode

* Add a Window > Reset Workspace action

* workspace_layout.json -> workspace_layout.ron

* Fix native app hole punch

* Cleanup review pass

desktop/wrapper/src/messages.rs

@@ -58,6 +58,10 @@ pub enum DesktopFrontendMessage {
 		preferences: Preferences,
 	},
 	PersistenceLoadPreferences,
+	PersistenceWriteWorkspaceLayout {
+		workspace_layout: String,
+	},
+	PersistenceLoadWorkspaceLayout,
 	UpdateMenu {
 		entries: Vec<MenuItem>,
 	},
@@ -117,6 +121,9 @@ pub enum DesktopWrapperMessage {
 	LoadPreferences {
 		preferences: Preferences,
 	},
+	LoadWorkspaceLayout {
+		workspace_layout: String,
+	},
 	MenuEvent {
 		id: String,
 	},