Improve the experience for using modern JS

[brianjhanson]

Adds two methods to the View class.

registerScriptWithVars

Mirrors registerJsWithVars but for registerScript because the JS method doesn't allow you to add type="module" to your script tag. This just makes it a little easier to deal with module JS in PHP

$view->registerScriptWithVars(fn($refHandles) => <<<JS
	import {setLocalizedRefHandles} from '@craftcms/ckeditor';
	setLocalizedRefHandles($refHandles);
JS, [$refHandles], View::POS_END, ['type' => 'module']);

registerJsImport

Allows registering key value pairs for a "module specifier map" to be injected via a <script type="importmap"> tag. Documents are only allowed to have a single import map at the moment, so we need a way to collect all of those specified by Craft + plugins and output them into a single script tag. The import map must also be declared before any script tags, so we add it before any scripts registered with the View::POS_HEAD position.

More on import maps can be found here