MDL-31860 mod_forum add advanced grading feature to forum
Allow students to view grading info.
remove custom grading class
Different method of changing available methods no grade string.
add aggregate methods to UI
MDL-31860 Fix calls to grading manager and remove empty line from install.xml
Revert "add aggregate methods to UI"

This reverts commit cd384bfd1c7fa94cd5357c39bb4a51cf7667b180.

Conflicts:
	course/modedit.php
mod/forum: add behat test
MDL-47372 Add self grading field and setting.
Allow self-grading in forum
MDL-47372 mod_assign: allow self grading in assignment.
Make sure grade header appears when advanced grading enabled.