Add Firebase Authentication

[xyliew25]

• Environment: live server at V8.17.0

Description of feature/enhancement
An authentication solution that supports any domains on top of Google social accounts.

Justification
This feature/enhancement benefits users without Google accounts or users who are not willing to use their (likely personal) Google account from using the system.

Existing similar features and their shortcomings
Only Google social account is supported as a form of identity provider.

More info can be found on the wiki at https://github.com/TEAMMATES/teammates/wiki/Authentication-Plus.

[Abhijeetmishr]

@xyliew25 Is anyone working on this from backend ?

[xyliew25]

@Abhijeetmishr hi, yes, I'm currently working on this issue. PR #11891 includes changes required for the back end as well.

[Abhijeetmishr]

@Abhijeetmishr hi, yes, I'm currently working on this issue. PR #11891 includes changes required for the back end as well.

@xyliew25 Ok thank you
I am new to this project & OpenSource any suggestion to pickup any issue from backend ?

[zhaojj2209]

@Abhijeetmishr We recommend starting from issues with the good first issue label on them!