Phase 2. Light dialog with copy-all-content option

The first time another language with no content is selected a dialog will appear to ask if you would like to copy all content (structured and unstructured) from the story into the new language. The user has two options, either to copy all content or to start from scratch.

User story:

As an author, I want to copy the blocks from the original language to a translation, so that I can translate faster.

Rationale:
Imagine a big set of blocks with many blocks containing things like videos, images, maps and other things that do not need to be translated. It would be a lot of work, annoying, and a waste of time if the author had to assemble that same collection of content all over again. A "block-copy" feature would bring over all the blocks from another language - and then the author can start with that content and translate all of the things that need translating.

Acceptance criteria:

• On switching to a new language for the first time, user can choose btw
  • Copy content (from master language)
  • Start without content