Pass newUser as parameter to sendVerificationRequest

[Abel1011]

Hi, thank you for this wonderful tool. I would like to submit a request to add a newUser parameter to sendVerificationRequest, this way we can customize the mail sent to the user when he is new.

I was reviewing the code in src/core/routes/signin.ts and before processing the email sending, getUserByEmail is called; at that point we can identify if the user is new and pass the parameter to sendVerificationRequest. This way we can save an additional call to the database.