Feature onboarding user

[cedricve]

Within this PR we will send the user information to the API (through an encrypted fingerprint).

1. The fingerprint is generated at the user creation/update, and send over with the signed url, so we are able to identify the user at the onboarding stage.
2. Once the user lands on the onboarding page, he/she will fill-in all the desired details and make a video recording.
3. All the information about the user and video identification is send to the /api/user/onboard endpoint together with the identification fingerprint.
4. The user is now marked onboarded, and the recording is used to extract the facial embeddings.

TODO's

• Add a status field to the user (@KilianBoute)
• Implement onboarding method: update user, store video.
• Generate a fingerprint on "sharing of the page", email generation will be done in a separate task.