feat(metrics): Add metrics for signup, preverified signup, signin, hide the resend button.

@kparlante - can you see if this is a bit closer to what you were looking for?

@nchapman or @zaach - could one of you do a pass over this as well?

Add:
* login.complete - for a user who signs in successfully.
* signup.preverified - for users who attempt to sign up with a preVerifyToken
* signup.preverified.complete - users who successfully sign up with a preVerifyToken
* signup.complete - users who complete the signup flow of any type.
* confirm_reset_password.resend - users who attempt to resend the password reset email.
* confirm_reset_password.too_many_attempts - when we hide the "Resend" button for password reset users who have tried too many attempts.

Hook up the debounce code to the password reset.

issue #1559
fixes #1147
Thanks @pdehaan!

I made that change for tangential reasons, and probably not a very good one. We use the className as a prefix on the "too_many_attempts" message. Since we use "_" instead of "-" in messages, I updated the className, which made the className inconsistent with other class names.