Create a corresponding Firefly action generator

Looking at the possibility to use the SDK within a Project Firefly app (e.g. for server-side rendering use-cases), we welcome PRs to our [application generators repository](https://github.com/adobe/generator-aio-app).

One idea would be to add a [generator for an action](https://github.com/adobe/generator-aio-app/tree/master/generators/add-action) that renders the delivered content server-side.

Start by reviewing the application generators repository, especially generators/add-action, and the AEM Headless Client for JavaScript SDK context. A corresponding Project Firefly action generator should be added that supports server-side rendering of delivered content; confirm the expected generator structure and behavior there before proceeding.

Written by the indexing model from the issue text.