Add 2FA to Mautic

[marcusquinn]

Not sure if this is the best solution but missing 2FA on Mautic makes me a little nervous for GDPR expectations.

• https://autoize.ch/2-factor-authentication-2fa-for-mautic/
• https://github.com/hostnetbr/mautic-googleauthenticator

[girish]

I guess this is a ask for the upstream developers? https://github.com/hostnetbr/mautic-googleauthenticator/tree/master/HostnetAuthBundle hasn't been updated for a while and since the Mautic 3 plugin API changed, that plugin won't work without further development.