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

course/format/renderer.php

@@ -448,6 +448,7 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
      */
     protected function get_nav_links($course, $sections, $sectionno) {
         // FIXME: This is really evil and should by using the navigation API.
+        $course = course_get_format($course)->get_course();
         $canviewhidden = has_capability('moodle/course:viewhiddensections', context_course::instance($course->id))
             or !$course->hiddensections;
 
@@ -542,6 +543,7 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         global $PAGE;
 
         $modinfo = get_fast_modinfo($course);
+        $course = course_get_format($course)->get_course();
 
         // Can we view the section in question?
         if (!($sectioninfo = $modinfo->get_section_info($displaysection))) {
@@ -637,6 +639,7 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         global $PAGE;
 
         $modinfo = get_fast_modinfo($course);
+        $course = course_get_format($course)->get_course();
 
         $context = context_course::instance($course->id);
         // Title with completion help icon.