cc+ exports and imports dealing with groups

Several tools have the ability to assign to groups. The preferred behavior on export/import is that empty groups are created in the import site and the group settings kept in each tool. Currently, the empty groups are not created on import with a cc+ file and group settings are not kept. https://sakaiproject.atlassian.net/browse/SAK-50975 deals with site info > import from site, while this Jira deals with the cc+ export/import.