Add WPUtilities dependency
Remove unused classes
Create a new cleaner file to clean clubs
Refactor importer class

To generalize this plugin, we removed some field of study-specific
functionality and renamed a lot of plugins and vars, and removed
the update/notify/diff strategies to simplify for now. See the
wp-fos-import plugin code or this history to bring this back.
Refactor main plugin file
Rename main plugin file