ERP5Workflow: Move back Transition Document to filesystem.

This will be needed for DCWorkflow to ERP5Workflow migration so this will be
a core Document and make bootstrap easier.
8 jobs for cmf_upgrade_versions
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

failed ERP5.UnitTest-Master

03:43:20

failed ERP5.UnitTest-Master.Medusa

passed SlapOS.Eggs.UnitTest-Master.Python2

00:11:58

passed SlapOS.Eggs.UnitTest-Master.Python3

00:30:02

failed ERP5.UnitTest-Master

passed SlapOS.Eggs.UnitTest-Master.Python2

00:34:17

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:01