Create auth proxies for handling user sessions

[lululeon]

For now, we will handle basic signup with username and password only. This ticket will create the api routes in the next js app for:

• forwarding username+password submissions to the API during signup events, and handling the response
• forwarding username+password submissions to the API during login events, and handling the response

Additionally:

• ensure usernames are unique across the app
• allow a flexible method for enforce password constraints (e.g. for now, > 8 characters in length)

Refs: https://v2.lucia-auth.com/guidebook/sign-in-with-username-and-password/

Entrance critieria

⌛ This ticket should wait for these dependencies to built:

• Implement Signup Route cbld-api#14
• Implement Login Route cbld-api#15
• Implement Logout route cbld-api#16

Acceptance criteria

• frontend is capable of passing information to cbld api and handling the response