Default marketing emails to true

[katjuell]

Description

Copy doc requests that this default to true.

Test process

Newly created users should be opted into digitalocean_marketing_emails

Requirements to merge

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code in hard-to-understand areas
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes