Implement Multi Factor Authentication (MFA)

[sbis04]

Showcase the new Firebase authentication method called Multi Factor Authentication (MFA), it gives users a more secure way of authentication. You can take the help of the Invertase blog present below inside the More info section.

Please try to maintain similar theming across the pages, though there aren't any concrete theming guidelines for this contribution but keep this in mind for future-proofing this contribution.

Use the correct folder structure for adding the functionality, have a look at the readme and the project lib folder structure to understand the proper folder structure to follow. Each functionality is under its own category and consists mainly of screens, utils, and widgets folders.

NOTE: You need to create your own Firebase project and configure it before starting to contribute, make sure you read the CONTRIBUTING guidelines.

More info: https://invertase.io/blog/flutterfire-mfa-tutorial
Package to use: https://pub.dev/packages/firebase_auth

Hacktoberfest 2022 Note: There's no assignment of issues (first come, first review basis), all eligible contributions will be given “hacktoberfest-accepted” label to make it count towards the Hacktoberfest contribution, even if it's not merged.