Add support for mobile authentication

[alice-hannah]

Likely requirement to add new wrapper function for /mobileauth/login endpoint.

API doc: https://secure.objectiveconnect.co.uk/publicapi/1/swagger-ui/index.html?configUrl=/publicapi/1/v3/api-docs/swagger-config#/MobileAuth

Blog: https://www.objective.co.uk/resources/blog-secure-any-users-login-credentials-with-account-mfa