Support webauthn (#17957)

Migrate from U2F to Webauthn

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/base/footer.tmpl

@@ -14,9 +14,6 @@
 	{{template "base/footer_content" .}}
 
 <!-- Third-party libraries -->
-{{if .RequireU2F}}
-	<script src="{{AssetUrlPrefix}}/vendor/plugins/u2f/index.js"></script>
-{{end}}
 {{if .EnableCaptcha}}
 	{{if eq .CaptchaType "recaptcha"}}
 		<script src='{{ URLJoin .RecaptchaURL "api.js"}}' async></script>