added google login and google drive sync

[nikhilchowdary]

Issue#395
1.Added google login functionality to get user's credentials :: profile pic , name and email account
2.Added google drive to sync drafts,apks and saved projects to the drive and upon completion of sync user recieve notifications of synced draft/project/apk.

[opticod]

@nikhilchowdary , Thanks for the PR. Its a good feature.

1. So suppose I have re-installed my app and old data is lost. Can now performing Sync will download the old data?

2. As this requires google app signing and registration. For now lets remove the source-code/app/google-services.json file from your commit. We will be adding it after adding the project in console.

[nikhilchowdary]

The sync feature is implemented only to upload the files to drive so that it can be used to manually download files from drive . Should I also include a download files option from the app itself

[opticod]

Naturally, there should be one option to update the contents of the phone from the cloud side too.

[nikhilchowdary]

@opticod
ok I will update the PR with download option.

[opticod]

@nikhilchowdary , are you still on this?