Add ability to create/login account via Firebase Authentication

[brianchang928]

Is your feature request related to a problem? Please describe.
In order to sync data across different devices.
Ex: Bookmarks (issue #11), user tickets, and even OneSignal's User Model.

Describe the solution you'd like
Create/Login account via Firebase Authentication and use Firestore to store and sync different data.
Also, use the account's uid to sync OneSignal's User Model via External ID.

Describe alternatives you've considered
N/A

Additional context
N/A