Describe the feature you'd like to request

When building your turbo.json config file, there is the point where it becomes pretty large to manage. It will be nice to have the alternative turbo.{js,ts} to programmatically skip code duplication, conditionally load a configuration setting, extract setting to an env-related module, etc. There are many advantages of having a ts/js config file that I don't think is worth mentioning all of them.

Describe the solution you'd like

turbo.js and/or turbo.ts as a developer choice in how it builds the turbo configuration.

Describe alternatives you've considered

None, besides extending the capabilities of the json settings but it will be quite a headache and most of the requirements needed are already covered in the language (js/ts)