Improve main training management ergonomics

[dcadiou]

It could be nice to have training management page splitted in 2 pages. The first (could be named 'training_view') to display various global informations about the current training, with an action menu containing :

• settings (which links to the second training management page, as the current training management page but with less settings, only global training settings such as training name, start date and end date, total time credit, and so on)
• courses (which could leads to a new page to add course (already existing feature) and perhaps remove some (to be developped)
• milestones (which link to the milestones management page)
• learners (which links to the learner management page)
• template (which links to a new template setting page, to select which template to use and various grouping settings)
• report (which links to global report page)
• save (to save the training as json export)
• restore (to import a training from a json backup)

The last 2 points are linked with issue #158 (save and restore features integration in the core plugin).

I think such ergonomics could be closer to usual Moodle ergonomics (as course view with it's action menu).