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>
Now content and course index sections have special mutations to store
the collapsed preferences. This way the backend implementation is
independent of the frontend one and can use caches or other kind of
optimizations of necessary.
Jason den Dulk