MDL-44725 Availability: Replace groupmembersonly - upgrade, core (1)
* Upgrades existing data so that the groupmembersonly option is replaced with equivalent data for the new availability API. * Removes the database field and admin setting used for groupmembersonly. * Changes core modinfo library to remove/deprecate groupmembersonly data and functions. * Changes other core library files to remove groupmembersonly references. Includes deprecation of several functions, listed in lib/upgrade.txt.