feat: add enabled option

[huang-julien]

Fixes #555 and fixes storybook-vue/storybook-nuxt#63.

Hi 👋 this PR adds an enabled option.

This can be useful for layers.
Some users have project A, B with A extending B that has storybook but is not needed in A. This can improve dev server startup as storybook can be quite heavy to load on bigger projects.

[netlify]

👷 Deploy request for nuxt-storybook pending review.

Visit the deploys page to approve it

Name	Link
🔨 Latest commit	be1bb48

[tobiasdiez]

Good idea, this would also resolve #555, right?

I'm not so sure about the name of the option. Currently, the module indeed only starts the storybook server - but that may change in the future. So I would prefer a name that reflects that only the storybook dev server can be disabled by this option. Tailwind has it under viewer. Maybe just also use viewer here for storybook? Or do you have better suggestion?

[huang-julien]

oh indeed.
About the name, i'm not convinced that viewer is a good name. This option just prevent the whole module from being run. viewer would fit an option that control if the module adds the storybook tab or not in the devtools.
I don't really have any other suggestion, but i think some other modules are also using enabled

[tobiasdiez]

Okay, if more fine-grained control is needed in the future, we can add another viewer/devserver/whatever option in the future.

Could you please add a short description of the option to https://github.com/nuxt-modules/storybook/blob/main/docs/content/1.getting-started/2.options.md (perhaps with your use case of layers as motivation). Otherwise this looks good from my side.

[tobiasdiez]

Thanks!