Improve checklist_print_overview()

1. Add a new global setting - show only updateable checklists
2. If that setting is enabled then CHECKLIST_MARKING_TEACHER checklists
will not be shown in 'my moodle' (check the type, then 'continue' the
loop)
3. If that setting is enabled and the user does not have the capability
'updateown', then skip that checklist ('continue' the loop)
4. 'CHECKLIST_MARKING_BOTH' checklists should also be hidden, as
students cannot affect the progress bar, only teachers can update the
progress bar.
5. Site Admin's will not see any checklist notices