ts: use pages modules in admin (kinda), change pseudo-links

pseudo-links are now just links, because i'm lazy and it's easier than
fixing an issue. They now take the form `/?invite=code` and
`/accounts/?user=userid`.

ts/modules.tabs.ts is now a wrapper for ts/modules/pages.ts.

Also, fixed no section appearing when visiting the settings tab.

ts/typings/d.ts

@@ -79,20 +79,10 @@ declare interface NotificationBox {
 
 declare interface Tabs {
     current: string;
-    tabs: Array<Tab>;
-    addTab: (tabID: string, preFunc?: () => void, postFunc?: () => void) => void;
+    addTab: (tabID: string, url: string, preFunc?: () => void, postFunc?: () => void) => void;
     switch: (tabID: string, noRun?: boolean, keepURL?: boolean) => void;
 }
 
-declare interface Tab {
-    tabID: string;
-    tabEl: HTMLDivElement;
-    buttonEl: HTMLSpanElement;
-    preFunc?: () => void;
-    postFunc?: () => void;
-}
-
-
 declare interface Modals {
     about: Modal;
     login: Modal;