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/pwr.ts

@@ -3,6 +3,7 @@ import { Validator, ValidatorConf } from "./modules/validator.js";
 import { _post, addLoader, removeLoader } from "./modules/common.js";
 import { loadLangSelector } from "./modules/lang.js";
 import { Captcha, GreCAPTCHA } from "./modules/captcha.js";
+import { setupTooltips } from "./modules/ui.js";
 
 interface formWindow extends Window {
     invalidPassword: string;
@@ -39,6 +40,8 @@ loadLangSelector("pwr");
 
 declare var window: formWindow;
 
+setupTooltips();
+
 const form = document.getElementById("form-create") as HTMLFormElement;
 const submitInput = form.querySelector("input[type=submit]") as HTMLInputElement;
 const submitSpan = form.querySelector("span.submit") as HTMLSpanElement;