Declare skin styles and scripts in the skin manifest as options

For you consideration. We will be aiming to do this in all Wikimedia
deployed skins so it would be great to have Timeless consistent with
those.

Change-Id: I11a8e0c8ca01b2c7eb2acc0b84ea4ad9301d3d8f

includes/SkinTimeless.php

@@ -17,10 +17,6 @@ class SkinTimeless extends SkinTemplate {
 	public function initPage( OutputPage $out ) {
 		parent::initPage( $out );
 
-		$out->addModules( [
-			'skins.timeless.js'
-		] );
-
 		// Basic IE support without flexbox
 		$out->addStyle( $this->stylename . '/resources/IE9fixes.css', 'screen', 'IE' );
 	}

skin.json

@@ -21,6 +21,9 @@
 					"styles": [
 						"mediawiki.skinning.content.externallinks",
 						"skins.timeless"
+					],
+					"scripts": [
+						"skins.timeless.js"
 					]
 				}
 			]