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/form.ts

@@ -5,6 +5,7 @@ import { loadLangSelector } from "./modules/lang.js";
 import { Validator, ValidatorConf, ValidatorRespDTO } from "./modules/validator.js";
 import { Discord, Telegram, Matrix, ServiceConfiguration, MatrixConfiguration } from "./modules/account-linking.js";
 import { Captcha, GreCAPTCHA } from "./modules/captcha.js";
+import { setupTooltips } from "./modules/ui.js";
 
 interface formWindow extends GlobalWindow {
     invalidPassword: string;
@@ -42,6 +43,8 @@ interface formWindow extends GlobalWindow {
     collectEmail: boolean;
 }
 
+setupTooltips();
+
 loadLangSelector("form");
 
 window.notifications = new notificationBox(document.getElementById("notification-box") as HTMLDivElement);