Add Google Authentication

[alph-a07]

• Only authentication method as of now, as only android users are targeted for now.
• Register and store users using supabase's auth service.
• Store users in supabase database

[alph-a07]

Not controlling authentication service from the backend, doing it on the client side

• Would be easier to implement
• Redundant

[alph-a07]

Store users validated by client finsible-frontend#1