Add model-viewer script via MW php method

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

includes/GlModelViewer.php

@@ -39,6 +39,11 @@ class GlModelViewer extends ImageHandler {
   public static function onBeforePageDisplay(OutputPage $out) {
     preg_match('/(<model-viewer src="\S*?\.(glb|gltf"))/',$out->getHTML(),$findGltf);
     if ($findGltf[0]) {
+      $mvScriptAttr = array(
+        'src' => 'https://ajax.googleapis.com/ajax/libs/model-viewer/3.5.0/model-viewer.min.js',
+        'type' => 'module'
+      );
+      $out->addHeadItems(Html::rawElement('script',$mvScriptAttr));
       $out->addModules('ext.glmv');
     }
   }
@@ -80,8 +85,6 @@ class GlModelViewer extends ImageHandler {
   public static function onImageOpenShowImageInlineBefore( $imagepage, $out ){
     $file = $imagepage->getFile();
     if ($file->getMimeType() == 'model/gltf-binary') {
-      $out->addModules('ext.glmv');
-
       $viewer = self::buildViewer($file->getDescriptionText(), $file->getFullUrl(), ['class' => 'view-default']);
       $out->addHtml(Html::rawElement('div',['id' => 'file', 'class' => 'fullModelView'],$viewer));
     }