feat: adds firebase auth

[sebastian-nunez]

Feat firebase auth

Description

Adds authentication via Firebase (login, sign up, logout)

Important: you will need to get GoogleService-Info.plist to be able to link up with Firebase locally

Changes

• creates UserService to fetch and upload user metadata
• creates AuthService to login/signup/logout using FirebaseAuth
• creates a User model
• adds some validation for email and passwords
  • no integration with UI or custom error, only console logs

Screenshots

Firestore Auth

Users can create an account with an email and password

Firestore Database (users collection)

This collection will hold all the metadata for users.

Note: username is generated by the prefix of the user's email (ex. johndoe@gmail.com -> johndoe)