request: Configurable firebase.json output directory ("--firebase-out=<PATH>")

### Is there an existing feature request for this?

- [X] I have searched the existing issues.

### Command

`flutterfire configure --yes --project= --firebase-out=`

### Description

As a developer, I want to be able to dictate where the `firebase.json` generated file is written to.

### Reasoning

This feature is useful for compatibility with projects with abnormal file structures, multi-environments, or special CI/CD instructions.

### Additional context and comments

The other generated outputs have path-supported flags:
```
flutterfire configure \
--yes \
--project=your-project-id \
--platforms=ios,macos,android,web \
**--android-out=android/app/src/release/google-services.json \**
--android-package-name=com.example.myapp.release \
--ios-build-config=Release \
**--ios-out=/ios/release/GoogleService-Info.plist \**
--ios-bundle-id=com.example.myApp.ios.release \
--macos-build-config=Release \
**--macos-out=/macos/release/GoogleService-Info.plist \**
--macos-bundle-id=com.example.myApp.macos.release \
--web-app-id=<1:XXX:web:XXX> \
**--out=lib/release/firebase_options.dart**
```

Supporting the `firebase.json` location would further future-proof the CLI.