MDL-36017 Fields numsections, hiddensections and coursedisplay are now format-specific options

- Fields added to format_legacy as default course format options;
- Upgrade script copies fields values from table course to course_format_options;
- Fields removed from table course;
- Fields removed from edit course form;
- Since front-page course has a 'numsections' setting, format_site defines it as it's option;
- Removed accessing those fields in core code unless we know that format supports them and in this
  case instead of $course = $DB->get_record('course'); we use:
  $course = course_get_format($courseorid)->get_course(); This way all format-specific options
  are added to the $course object

lib/filelib.php

@@ -3977,13 +3977,6 @@ function file_pluginfile($relativepath, $forcedownload, $preview = null) {
                 send_file_not_found();
             }
 
-            if ($course->numsections < $section->section) {
-                if (!has_capability('moodle/course:update', $context)) {
-                    // block access to unavailable sections if can not edit course
-                    send_file_not_found();
-                }
-            }
-
             $filename = array_pop($args);
             $filepath = $args ? '/'.implode('/', $args).'/' : '/';
             if (!$file = $fs->get_file($context->id, 'course', 'section', $sectionid, $filepath, $filename) or $file->is_directory()) {