Publication: Create preview step for publication

Currently, in the publication process there's a first step of setting the publication parameters and a second step for the actual publication. An intermediate step should be provided as a preview step.

It should:

• display the published book reference,
• display a list of used libraries and their versions, with a link to the libraries' management UI,
  • status of the libraries (= published or not).
  • if not published, a link to the library publication should be provided
  • for a configured library version, all the previous versions of this library should also be checked (for instance, if the version of the library is 3.0 in the configuration, 2.0 and 1.0 would also have to be checked). They might not be used, but can in case of inheritance.
• display a list of all the pages that are going to be published, based on the publication parameter, and their status
• depending on the selected behaviour (see BVERSION-83), if "Cancel" is selected, it might be good to display a message to the user (explaining that the target is already populated) and prevent him from running the job