config: start adding path parameters

to change the urls of the admin page, the my account page and of
invites. Seems to work, but need to check all the code over and test.

ts/setup.ts

@@ -3,12 +3,11 @@ import { lang, LangFile, loadLangSelector } from "./modules/lang.js";
 import { ThemeManager } from "./modules/theme.js";
 import { PageManager } from "./modules/pages.js";
 
-interface sWindow extends Window {
+interface sWindow extends GlobalWindow {
     messages: {};
 }
 
 declare var window: sWindow;
-window.URLBase = "";
 
 const theme = new ThemeManager(document.getElementById("button-theme"));