Upgrade the support for Open Badges 2 to support a real open badges 2 backpack.
Moodle can only talk to one backpack at a time, so after switching backpacks, users
will have to manually disconnect and then reconnect their backpack to the new one.
This commit combines several changes:
* Split classes into badges namespace
* Publish expiry data with a badge
* Publish badge alignments in badges exported to the backpack.
* Export the criteria for a badge to the backpack.
dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
Preferences pages cancel and continue buttons should lead back to preferences page.
Site pages should have consistent headers and breadcrumbs.
Hide the "Preferences" node in the navigation.
Part of MDL-45774
The badges feature allows to integrate Mozilla "Open Badges" to issue, assign,
manage and display digital badges in Moodle. This feature supports:
-- badge creation and issuing based on criteria
-- badge baking and verification service
-- direct pushing of internal badges to external backpack
-- interanl and external badge display in Moodle
-- Moodle block to display latest badges
