MDL-39759 REST SERVER HTTP response code

Moodle should response 403 if web service or REST protocol not enabled
MDL-44669: mod/assign: fix batchoperations JS when using select all checkboxes.
MDL-31679 gradereport_grader: Add a horizontal scroll bar to the top of the grader report
MDL-29572 Grade Import: Avoid creating invalid temporary rows; Provide feedback on error
MDL-44507 filemanager: indicator for clicking Download All in filemanager
MDL-41123 report_completion: Add events to completion report

Replace add_to_log with user_report_viewed event
add a report_viewed event
MDL-41123 report_completion: Add context validations to the events
MDL-44927 Atto: Table editor typo that prevents creation of new tables.
Merge branch 'MDL-29572_master' of https://github.com/jrchamp/moodle
Merge branch 'MDL-44507_master' of https://github.com/SWiT/moodle

Conflicts:
	theme/bootstrapbase/style/moodle.css
MDL-44507 filemanger: fix coding style
Merge branch 'MDL-39759_http_response_code_master' of https://github.com/dongsheng/moodle
Merge branch 'MDL-31679' of git://github.com/aolley/moodle

Conflicts:
	theme/bootstrapbase/style/moodle.css
Merge branch 'mdl44669-master' of https://github.com/tlock/moodle
Merge branch 'MDL-41123-master' of git://github.com/ankitagarwal/moodle
MDL-44268 assign: add 'not submitted' and 'no marker' filter options
MDL-44268 Assign: Improve the "not submitted" filter
MDL-44268 Assign: Fix behat test for assigned marker filter
MDL-44070 availability: corrected SQL to be mysql-compatible
MDL-42195 Bootstrap: Make selector for responsive images 100% the same as bootstrap3.