FlutterFire Pub Integration

[kylermintah]

Description:

We are using the FlutterFire pub to register and log users into the app. We need to integrate the Firebase packages in such a way that a user's session is accounted for (online status). The implementation no longer needs to be done and maintained separately on iOS and Android due to the encompassing nature of the FlutterFire pub packages and Firebase offerings unlike the initial approach detailed in #34.

Requirements to start: none

Requirements for completion:

• [x] Package integrated and tested for iOS
• [x] Package integrated and tested for Android
• [x] Users can register through EventHopper API endpoint
• [x] Users can perform account/data deletion through EventHopper API endpoint
• [x] User log ins are recorded through Firebase
• [x] User log outs are recorded through Firebase

[kylermintah]

Completed