This just deletes all the upgrade steps previous to 2.7.0. Some
small adjustments, like adding missing MOODLE_INTERNAL or tweaking
globals can also be applied when needed.
Next commit will get rid of/deprecate all the upgradelib functions
not used anymore in codebase.
1. Change behaviour admin settings so you can only select enabled
behaviours.
2. During the upgrade, change admin settings that might be currently set
to manual graded, so that instead they are set to deferredfeedback (if
that is available. If not, we just take the first alphabetically.)
The ability to set all your quiz questions to require manual grading is
an interesting possibility, but practically almost useless.
If you set that accidentally, then you are badly stuck. There is no way
to fix it after the students have answered the quiz.
Therefore, we should set the config option to hide that option from the
UI. We do this for all Moodle sites as part of the upgrade, not just for
new installs.
If any admin wants to re-enable this, they can later.
