Identifies and authenticates a user and returns an authentication token.
Requires an identity value (email, phone, username) and authenticator method (email, password, sms).
If the authenticator is a password, an additional secret is provided. A device and PIN is always required.
If this is a one-step authentication, the token will be included in the response. If this is a two-step authentication, the token will not be available until a secret has been provided using the /tokens/{id}/secret endpoint.

Validation errors:

• field_identity: missing
• field_authenticator: missing
• field_device: missing