Add authentication + saved maps

[emi420]

Implement authentication using HOT Accounts - based on Hanko (https://github.com/hotosm/login)

• Link to login on the header
• User avatar on the header when logged in
• Profile + link to logout

[linear]

TECH-885

[emi420]

• Check if it's possible keep the data trough the auth process
• If not, worst case scenario, create an anonymous map