Clean up WebAuthn javascript code and remove JQuery code (#22697)

There were several issues with the WebAuthn registration and testing
code and the style
was very old javascript with jquery callbacks.

This PR uses async and fetch to replace the JQuery code.

Ref #22651

Signed-off-by: Andrew Thornton <art27@cantab.net>

---------

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: silverwind <me@silverwind.io>

web_src/js/utils.js

@@ -1,3 +1,5 @@
+import {encode, decode} from 'uint8-to-base64';
+
 // transform /path/to/file.ext to file.ext
 export function basename(path = '') {
   return path ? path.replace(/^.*\//, '') : '';
@@ -135,3 +137,17 @@ export function toAbsoluteUrl(url) {
   return `${window.location.origin}${url}`;
 }
 
+// Encode an ArrayBuffer into a URLEncoded base64 string.
+export function encodeURLEncodedBase64(arrayBuffer) {
+  return encode(arrayBuffer)
+    .replace(/\+/g, '-')
+    .replace(/\//g, '_')
+    .replace(/=/g, '');
+}
+
+// Decode a URLEncoded base64 to an ArrayBuffer string.
+export function decodeURLEncodedBase64(base64url) {
+  return decode(base64url
+    .replace(/_/g, '/')
+    .replace(/-/g, '+'));
+}