Move JavaScript code into explicit namespaces

This cleans up the global namespace by explicitly exporting shared values. All html and JavaScript files have been converted to use explicit exports except for client.js and mocha-init.js

src/webui/www/private/scripts/mocha-init.js

@@ -38,7 +38,7 @@
    ----------------------------------------------------------------- */
 'use strict';
 
-const LocalPreferences = new LocalPreferencesClass();
+const LocalPreferences = new window.qBittorrent.LocalPreferences.LocalPreferencesClass();
 
 let saveWindowSize = function() {};
 let loadWindowWidth = function() {};