tooltip: rework as pseudo-component, fix overflow

uses the <tool-tip> tag now, and the setupTooltips() function in ui.ts
must be called at any point in the pages load. added "below-center"
position, showing below and centered horizontally. breakpoint tailwind
lingo also now works (e.g. "below-center sm:right"). If a left or
right-aligned tooltip clips off the screen, it will be shifted the
appropriate amount left/right to avoid that automatically.

ts/admin.ts

@@ -10,9 +10,12 @@ import { ProfileEditor, reloadProfileNames } from "./modules/profiles.js";
 import { _get, _post, notificationBox, whichAnimationEvent, bindManualDropdowns } from "./modules/common.js";
 import { Updater } from "./modules/update.js";
 import { Login } from "./modules/login.js";
+import { setupTooltips } from "./modules/ui.js";
 
 declare var window: GlobalWindow;
 
+setupTooltips();
+
 const theme = new ThemeManager(document.getElementById("button-theme"));
 
 window.lang = new lang(window.langFile as LangFile);