Northstar integration for POST `/api/v1/email` user details

[deezone]

Enhance /api/v1/email endpoint for sending transactional email to:

• accept user_id rather than email as required field
• lookup optional user related parameter values
• POST /api/v1/email - trigger sending transactional email message
  • Required fields
  • activity : [user_register]
  • email OR user_id : email address OR Northstar user ID
  • Optional fields to be populated by Northstar if not supplied
  • first_name (FNAME - defaults to "Doer" if Northstar doesn't supply a value)
  • user_country (defaults to US if Northstar doesn't supply a value))
  • user_language (defaults to enif Northstar doesn't supply a value)

Related Northstar Endpoints

• GET /users/_id/<user_id>
• GET /users/email/<email>

Reference:

• https://github.com/DoSomething/northstar/blob/dev/documentation/endpoints/users.md#retrieve-a-user

[sergiitk]

Closing it, if favor of the new API structure: https://github.com/DoSomething/quicksilver-api/blob/master/documentation/endpoints/user.md