Throw errors on storybook start if @babel/core or babel-loader are not installed as dependencies

[Yankovsky]

Is your feature request related to a problem? Please describe.
@babel/core and babel-loader are peer dependencies for storybook. People can miss storybook installation instructions or later delete these dependencies because they are not used in project directly. There are many issues because of it, e.g. #6967 and #7058

Describe the solution you'd like
I suggest adding some friendly reminder if @babel/core and babel-loader are not installed as dependencies in project. Consider create-react-app notification on different version of required dependency

We can run something similar on storybook start.

Describe alternatives you've considered
I know that there are notifications about missing peer dependencies but they are easy to ignore.
If we could turn them into errors it would be much better but I don't know if there is such flag in package.json or in npm install command.

Another approach would be to turn peerDependencies into real dependencies. What are implications of this approach?

Are you able to assist bring the feature to reality?
Yes, I can.

[github-actions]

Automention: Hey @Keraito, you've been tagged! Can you give a hand here?

[shilman]

Throwing errors up front is a good idea -- I imagine it can save people time. Can you create a PR for it? I don't think converting peerDependencies is a good idea but I can't recall the rationale for it. I'm sure @Hypnosphi remembers :)

[Yankovsky]

I can work on this issue but first I want to understand why these dependencies are peer dependencies and I'll try to find a way to turn peer dependencies warning for package into errors.

[Hypnosphi]

We need those as peer dependencies as long as we're going to support both babel 6 and babel 7 configs

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[Yankovsky]

Ok ok bot, I'll try to do something with that issue.

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[stale]

Hey there, it's me again! I am going close this issue to help our maintainers focus on the current development roadmap instead. If the issue mentioned is still a concern, please open a new ticket and mention this old one. Cheers and thanks for using Storybook!