Add paranoid flag to options

[divagueame]

Hi, this is my attempt to tackle the paranoid option to hide user existence when requesting token on Sep 21
When the paranoid flag is enabled, and a user tries to sign in with a non existing email:

• The same behavior will be shown to the user.
• No email will be sent to non existing emails/user.
• A session will still be created for non existing emails/user. I am not sure how big of a deal it is, so I left it like that for now.

[mikker]

Thank you for this. I appreciate how you've done this with the least amount of changes possible. My only concern is the mocked instance var, however I feel it's worth thinking about whether we can do this without it.

[mikker]

While this is a clever solution I also think it's a little bit too invasive, I guess. I wonder if we can come up with another solution that completely avoids having to mock anything?

[mikker]

Thank you for contributing. This feature was implemented in #196 and released in 1.3.0