Phase 1: Ability to choose a language and create a translation

 User stories:

As an author I can enter content in multiple languages.

As a developer I can configure a content editor for multiple language support.

Acceptance criteria:

• Support the Magnolia standard way to enable multilanguage content in the Stories app --> Should be covered by CONTEDIT-389
  • Outline fields that do not have the i18n property should have the same value in every language. Rationale: Outline fields such Author, Date and Location are often not translated. They have the same value across translations.
  • Validate user input in outline fields the same way we do in a typical form. When a user switches between languages Magnolia should validate the input. For instance, alert the user if a required outline field is empty.

Out of scope from this ticket

• Provide a language selector dropdown in the lower left corner of the editor subapp, see design –> Now CONTEDIT-393
• There is no link between blocks of different languages --> Now CONTEDIT-394