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

index.php

@@ -98,6 +98,7 @@
     echo $OUTPUT->header();
 
 /// Print Section or custom info
+    $site = course_get_format($SITE)->get_course();
     $modinfo = get_fast_modinfo($SITE);
     $modnames = get_module_types_names();
     $modnamesplural = get_module_types_names(true);
@@ -107,7 +108,7 @@
     if (!empty($CFG->customfrontpageinclude)) {
         include($CFG->customfrontpageinclude);
 
-    } else {
+    } else if ($site->numsections > 0) {
         if ($editing) {
             // make sure section with number 1 exists
             course_create_sections_if_missing($SITE, 1);