Implement Forgot password and Forgot username

[kiner-shah]

• If user forgets their password, then ask for username and email id, check if they are valid. Then, send a mail on that email id containing link to reset password.
• Alternative approach, instead of sending a link, OTP can be sent and later verified.
• If user forgets their username, then ask for email id, check if it's valid. Then, send a mail on that email id containing the username.