Generating multiple files from a `list` type

Hi!

I have this question about generating a list of files, but after search on docs and other issues, I think this is not implemented. Or maybe I do it in the wrong way... 🤔
I create this bug as a bug, but feel free to label it correctly if I miss something.

**Description**
I want to generate a list of files, from a `list` param in the `brick.yaml` file. This will allow the user of the brick to generate multiple files with the same logic inside.

For example, we want to generate multiple models from a brick called `generate_data_models`, with the following `brick.yaml` file:
```yaml
name: generate_data_models
description: Creates a new data models
version: 0.1.0+1

environment:
mason: ">=0.1.0-dev.51 <0.1.0"

vars:
data_folder_name:
type: string
description: Name of the data folder to put the model files inside.
prompt: What is the data folder name?
models:
type: list
description: List of models, used to create basic model class files.
prompt: What are the models names to create (separated by comma)?
separator: ","
```

And the following brick tree:
```sh
.
├── CHANGELOG.md
├── LICENSE
├── README.md
├── __brick__
│   └── lib
│      └── data
│      └── {{data_folder_name.snakeCase()}}
│      ├── data
│      │   └── data.dart
│      ├── models
│      │   ├── models.dart
│      │   └── {{#models}}{{..snakeCase()}}.dart{{
│      │   └── models}}
│      └── {{data_folder_name.snakeCase()}}.dart
└── brick.yaml
```

When I generate the code from this brick, this will create the following tree (inspired by the [Weather tuturial](https://bloclibrary.dev/#/flutterweathertutorial)):
```sh
lib/data
└── open_meteo_api
├── data
│   └── data.dart
├── models
│   ├── location.dartweather.dart
│   └── models.dart
└── open_meteo_api.dart
```

The expected output will be two separated files generated for `location` & `weather`:
```sh
lib/data
└── open_meteo_api
├── data
│   └── data.dart
├── models
│   ├── location.dart
│   ├── models.dart
│   └── weather.dart
└── open_meteo_api.dart
```
Plus, inside each file we want to access to the current `model` to generate the relevant code class code for this model.