Cleanup peerDependencies

[benmccann]

@storybook/source-loader doesn't need to be in peerDependencies because it's already in dependencies

@storybook/core-common and @storybook/node-logger can be just regular dependencies instead of peerDependencies since we don't need the user to add them to their package.json

@storybook/mdx1-csf doesn't need to be downloaded by all users. Users will use either @storybook/mdx1-csf or @storybook/mdx2-csf so move it to devDependencies so that users won't end up including it automatically

[IanVS]

Thanks for the cleanup. The only one I don't think we can move is @storybook/mdx1-csf. Since we require a particular version.