Clone story

[rodmaia]

Allow people to clone a story to create new stories quicker

Tasks

• [ ] Start an "add story" flow, and prepopulate the content with a copy of the original story
• [ ] Add a "_2" (or equivalent trailing counter) to the story name, to avoid duplication
• [ ] Allow saving only if the story is different from all other stories

Acceptance criteria

• [ ] New story is correctly added to the bot content, and updated result can be seen on DB