feature: preview environments

[elevatebart]

Is your feature request related to a problem? Please describe

When we set up a website with nuxt-content, it is useful to have preview environments setup. One for each PR sent our way.
If they share the same database, their data will collide.
When one will start, the other will die and need resetting.

Describe the solution you'd like

A way to pass a prefix to collection names at build time so the collection have their env in the name:

_content_docs would become _content_feat_new_blog_post_docs

could this be done through an environment variable?

Describe alternatives you've considered

Creating a new database programmatically for each environment.

Another alternative is to home bake it directly in the config. It feels awkward.

Additional context

n/a