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>

frontend/src/main.ts

@@ -20,7 +20,7 @@ import App from "@/App.vue";
 			}
 			</style>
 			<h2>This browser is too old</h2>
-			<p>Please upgrade to a modern web browser such as the latest Firefox, Chrome, Edge, or Safari version 15 or later.</p>
+			<p>Please upgrade to a modern web browser such as the latest Firefox, Chrome, Edge, or Safari version 15 or newer.</p>
 			<p>(The <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array#browser_compatibility" target="_blank"><code>BigInt64Array</code></a>
 			JavaScript API must be supported by the browser for Graphite to function.)</p>
 			`;