Projects appsettings.json file checked in by default

[Stevenic]

Describe the bug

There's no .gitignore file added to the root of new composer projects. This results in the projects appsettings.json being checked in by default. That file can contain access tokens and authoring keys which makes checking it in a security risk. We should add a default .gitignore file to the root of the project that prevents this file from being checked in.

Version

1.0.0

[VanyLaw]

I think the .gitignore file can prevent user mis-upload the appsettings.json file. But the sensitive value will still be persisted in appsettings.json file. So, I will remove those value in file and save in browser localStorage.