Initial signal* methods implementation available on Chrome

Hello WebAuthn connoisseurs,

An initial implementation of the signal* family of methods
<https://w3c.github.io/webauthn/#sctn-signal-methods> is now available on
Google Chrome. Please follow these instructions
<https://github.com/w3c/webauthn/wiki/Experimenting-with-the-Signal-API-on-Chrome>
if you want to try it or see the demo site
<https://signal-api-demo.glitch.me/>.

At this time, only Google Password Manager is supported, and only on
desktop. Passkeys marked as obsolete will be permanently removed, but we
have plans to hide them instead to make the operation reversible in the
near future.

We expect multiple revisions and changes before and after shipping, and as
always, your feedback is appreciated.

Have fun breaking things,
-- 
Nina Satragno