Welcome screen, refactor to allow zero documents, and add TS typing to widgets (#702)

* unfinished implementation

* Add frontend for the empty panel screen

* Add an icon for Folder based on NodeFolder

* fixed messages causing peicees of ui not to render on new document

* Standardize nextTick syntax

* WIP generisization of component subscriptions (not compiling yet)

* Fix crash when loading font and there is no active document

* Only advertise tool actions with a document

* Fix failure to create new document

* Initalise the properties panel

* Fix highlight tab, canvas jump, warns and layer tree

* Fix tests

* Possibly fix some things?

* Move WorkingColors layout definition to backend

* Standardize action macro formatting

* Provide typing for widgets in TS/Vue and associated cleanup

* Fix viewport positioning initialization

* Fix menu bar init at startup not document creation

* Fix no viewport bounds bug

* Change !=0 to >0

* Simplify the init system

Closes #656

Co-authored-by: Keavon Chambers <keavon@keavon.com>
Co-authored-by: 0hypercube <0hypercube@gmail.com>

editor/src/layout/layout_message_handler.rs

@@ -55,6 +55,10 @@ impl LayoutMessageHandler {
 				layout_target,
 				layout: layout.clone().unwrap_widget_layout().layout,
 			},
+			LayoutTarget::WorkingColors => FrontendMessage::UpdateWorkingColorsLayout {
+				layout_target,
+				layout: layout.clone().unwrap_widget_layout().layout,
+			},
 
 			#[remain::unsorted]
 			LayoutTarget::LayoutTargetLength => panic!("`LayoutTargetLength` is not a valid Layout Target and is used for array indexing"),
@@ -168,6 +172,7 @@ impl MessageHandler<LayoutMessage, ()> for LayoutMessageHandler {
 						responses.push_back(callback_message);
 					}
 					Widget::Separator(_) => {}
+					Widget::SwatchPairInput(_) => {}
 					Widget::TextAreaInput(text_area_input) => {
 						let update_value = value.as_str().expect("TextAreaInput update was not of type: string");
 						text_area_input.value = update_value.into();