While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.
All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.
Modified course format options reading and writing to be able to handle Editor elements by enabling them to split array values into
multiple values before inserting into database, and combining multiple values into an array when reading from the database.
Modified backup and restore code to use backup_nested_elements, and to interact directly with the database.
Co-authored-by: Jason den Dulk <jasondendulk@catalyst-au.net>
Co-authored-by: Matthew Hilton <matthewhilton@catalyst-au.net>
