[Auth] Send an email to user when added to passlist

[VictoriaOBRIEN]

Could you please add a notification for new users once their access has been granted?
Many thanks

[gino-m]

@VictoriaOBRIEN Do you want to send an email or an Android notification? The latter won't be possible until the user is signed in, which they can't do unless they're in the passlist.

[gino-m]

Having some issues with Cloud Functions, @rfontanarosa having some issues using their SMTP server.

[kenstershiro]

New Outlook email account obtained through CSI, able to send emails without paying. BE part ready to push
Questions on customization of email template.

[gino-m]

@vittorino @amegantz Can you help with designing the email sent to users when they're added to the passlist? It would need to contain a message for organizers to use the web app, for data collectors to use the Android app. @rfontanarosa will paste the current draft here.

@rfontanarosa I think it's ok to send a PR with what you have as-is to the main (this) repro. I would just move the mail config from /config/mailServer to /config/email and add this template to /config/email/templates/passlisted.

[kenstershiro]

Basic functionality is already in Prod, needs some tests