[Project SfC]: Implement a formatter to format new/edited files

[valentinpalkovic]

As a user, I want to have correctly formatted files after Storybook edits story files or creates new ones.

1. Format with prettier if available

If we can resolve a prettier config, we will format the file with prettier. We will resolve the user's installed prettier version to load their prettier file and to format files before saving them.

2. Basic formatting by considering .editorconfig

If we can't find a prettier config, we will format the file by taking into account the settings in the user's .editorconfig for basic formatting. The editorconfig has properties to define end_of_line, tab_width, indent_size, indent_style, trim_trailing_whitespace and insert_final_newline.

Requirements

• Provide a helper util in @storybook/core-common to format the content of a file by following the rules mentioned above.
• When an error occurs, the content should be returned without any formatting.