Manage backpacks page wasn't displaying the navigation and administration
menus when using classic theme (it's unrelated to changes done here).
This patch fixes this unexpected behaviour (raised thanks to behat tests).
Before removing $CFG->badges_site_backpack setting, admins should be
able to re-order the existing site-backpacks (because then, the first
one will be treated as the default one).
This patch adds the sort order feature to the backpack list.
Instead of running the site backpack validation every time badges/backpacks.php
page is loaded, an action button has been added to the backpacks with OB set
to 2.0 to let admins running manually this verification when needed.
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.
