* Rename classes and files to match model names, and removed workflow engine.
* Some fields should be readonly if not in draft.
* Allow Knowledge / Manager to edit previous history names and summary
* Improve ux by adding user_has_drafts to document pages.
* Changes because of implementation of active field on document_page
* Add ir.rules for document.page.history
* Allow to quickly cancel&draft from 'to approve' state
* FIX BUG: am_i_approver was being run as sudo(), hence always giving the user Approving rights.
* FIX hooks
Because of default='draft' on the state field, state IS NULL wasn't selecting anything.
Left the condition in case this is changed in the future.
* Lint error corrected
* test improved
* lint error corrected in test file
* readme corrected
* test improved
* test of document page history workflow added
* CI error corrected
* dreipst comment
* Migration to new api improved in model's file and data tag remove in xml file
* code totally migrate to odoo 9.0 api
* test bug fixed
* test error fixed
* Lint error improved
