Fix the bug related to opt-in box in registration flow

On the GitLab.com regular registration flow & the new trial sign up flow there is a registration page that asks "I want to receive updates by email from GitLab" only when this checkbox = true is the record supposed to be pushed to Marketo.

Issue

At this time, any time the registration flow in both scenarios will push to Marketo. This is creating a lot of low quality records that don't belong in the Marketing/Sales database.

Fix

In the regular registration workflow, only when the box = true should record push to Marketo, otherwise record stays w/in the user table and does not create a record in Marketo.

In the new trial registration workflow, only when the entire free trial steps are completed will the record be pushed to Salesforce.
- IF the I want updates box = true then the SFDC record needs to mark newsletter = true (SFDC API name = newsletterSegment)