Move libraries css files to sass

src/libraries/navdrawer/navdrawer.js

@@ -5,7 +5,7 @@
 /* eslint-disable no-var */
 import browser from '../../scripts/browser';
 import dom from '../../scripts/dom';
-import './navdrawer.css';
+import './navdrawer.scss';
 import '../../assets/css/scrollstyles.scss';
 
 export function NavigationDrawer(options) {

src/libraries/screensavermanager.js

@@ -4,7 +4,7 @@ import { pluginManager } from '../components/pluginManager';
 import inputManager from '../scripts/inputManager';
 import * as userSettings from '../scripts/settings/userSettings';
 import ServerConnections from '../components/ServerConnections';
-import './screensavermanager.css';
+import './screensavermanager.scss';
 
 function getMinIdleTime() {
     // Returns the minimum amount of idle time required before the screen saver can be displayed