Sara Arjona a26cfe71d3 MDL-65809 upgrade: clean < 3.5.0 upgrade steps
This just deletes all the upgrade steps previous to 3.5.0. Some
small adjustments, like tweaking globals can also be applied
when needed.

Also includes an upgrade step to prevent upgrading from any
version < 2018051700 (v3.5.0) as anti-cheating measure.

Previous commits have removed/deprecated all the upgradelib functions
not used anymore in codebase. Deletion has been documented in corresponding
upgrade.txt files:

- upgrade_fix_block_instance_configuration()
- upgrade_theme_is_from_family(), upgrade_find_theme_location()
and linkcoursesectionsupgradescriptwasrun setting
- upgrade_block_positions
- upgrade_fix_config_auth_plugin_names()
 and upgrade_fix_config_auth_plugin_defaults()
- format_xxx_upgrade_remove_numsections(), format_xxx_upgrade_hide_extra_sections()
and format_xxx_upgrade_add_empty_sections()
- filter_mathjaxloader_upgrade_cdn_cloudflare()
and filter_mathjaxloader_upgrade_mathjaxconfig_equal()
- get_assignments_with_rescaled_null_grades()

These have been kept because continue being used by restore:

- \core\task\refresh_mod_calendar_events_task
2019-12-20 12:20:43 +01:00
..

ACTIVITY MODULES
----------------

These are main modules in Moodle, allowing various activities.


Each of these modules contains a number of expected components:

  mod_form.php: a form to setup/update a module instance

  version.php: defines some meta-info and provides upgrading code

  pix/icon.gif: a 16x16 icon for the module

  db/install.xml: an SQL dump of all the required db tables and data

  index.php: a page to list all instances in a course

  view.php: a page to view a particular instance

  lib.php: any/all functions defined by the module should be in here.
         constants should be defined using MODULENAME_xxxxxx
         functions should be defined using modulename_xxxxxx

         There are a number of standard functions:

         modulename_add_instance()
         modulename_update_instance()
         modulename_delete_instance()

         modulename_user_complete()
         modulename_user_outline()

         modulename_cron()

         modulename_print_recent_activity()


If you are a developer and interested in developing new Modules see:

   Moodle Documentation:  http://moodle.org/doc
   Moodle Community:      http://moodle.org/community