Register using e-mail address

[joepio]

• [x] Use /register and /confirm-email endpoints
• [ ] User can Register using one button
• [ ] Create new drives the new way
• [ ] Remove / change old invite system. Maybe it still should work, but it needs a refactor at least. We at least want users to create a Drive from an agent without an e-mail address.

PR Checklist:

• [x] Link to related issue closes atomicdata-dev/atomic-server#640 closes atomicdata-dev/atomic-server#641
• [ ] Add changelog entry linking to issue
• [ ] Added tests (if needed)
• [ ] (If new feature) added in description / readme