copy story for the variant cover sequence

[jochengcd]

When adding a variant issue, there is no option to copy from another issue. Variants are limited so that only a cover sequence can be added to it, but often I find that I am adding the same cover sequence with the same artist, feature, genre, and characters as existing issues.

[jochengcd]

The workflow needs currently that the issue has an issue_id, so first the issue needs to approved before we can copy stories.