Takes three parameters, Login, Password, bRememberMe
Used to facilitate logging in (creating a new session) via API calls, as this function returns false (blank value) if the login successful, and any other value is a login error message to display to the user.
If successful, all aspects of the login, including creating the session, setting the outbound cookies, will be done for you. Internal runtime values such as $SessionUser, will be updated and ready to use.
The returned login error message if the login is successful but the user must complete a two factor authentication (TFA) step, will be formatted as follows:
TFA: You have logged in successfully, but now need to complete your login with this Check Number: 000 000
[New] LoginErr = Login$ Username, Password, bRememberMe
[New] LoginErr = Login$ Username, Password