Remove jshint - move everything over to eslint

Also removed all hints of previous linters

js/about_start.js

@@ -1,3 +1,5 @@
+/* global $: false */
+
 // Add version
 $('.version').text(`v${window.getVersion()}`);
 
@@ -14,7 +16,9 @@ if (window.getAppInstance()) {
 $('.environment').text(states.join(' - '));
 
 // Install the 'dismiss with escape key' handler
-$(document).on('keyup', function(e) {
+$(document).on('keyup', e => {
+  'use strict';
+
   if (e.keyCode === 27) {
     window.closeAbout();
   }