When we import courses or duplicate activities, the deduplicating nature of
the file_storage system means that we don't actually have to include the
real files in the backup - just their metadata from the file table.
The restoration process needs to know not to expect files from the backup
phase so a flag is set in moodle_backup metadata.
Some modes of backup cannot be preloaded with general backup
settings because they may conflict with the definitions required/set
by the mode (for example, import backups are, by definition, without
users always, so we cannot apply one default in the opposite direction).
So, after the patch, current general_backup setting will be only applied
to general backups, import/hub modes won't be using any default and
automated backup defaults should be loaded here (TODO)