Remove ReCaptchaLoginFilter

[MikeAlhayek]

Fix #15702
Fix #12705

Beside fixing thee two referenced issues, here is a summary of improvements

• We now honor IdentityOptions.User.RequireUniqueEmail where we did not in the past.
• Removed the ReCaptchaLoginFilter and converted the following views to shapes
  • ForgotPassword.cshtml
  • Register.cshtml
  • ResetPassword.cshtml
• Users can now reset their password using either a username or email address. In the past, only email address was allowed.