UP-4142 Group import changes

https://issues.jasig.org/browse/UP-4142
https://issues.jasig.org/browse/UP-4159
https://issues.jasig.org/browse/UP-4160

Changed crn script for group and group membership import to allow changes to group membership to update caches.

To do (do not hold up pull request processing for this):
* Test in clustered uPortal situation to verify imports on one node clear caches on other nodes
* Test if ant import-data will flush caches on uPortal nodes (optional but desirable)
It has to do with the current duplication of group data between required_entities and quickstart_entities.  In particular it affects groups of portlets.  When I did not have this, the portlet groups would be empty.  Portlet definitions in required_entities would add portlets to portlet groups, then repeat definitions of the portlet groups in quickstart, such as Academics, would remove all the members of added during required_entities/portlet-definitions.  At this point I don't see trying to fix the data as the best solution.  The use case (removing all members as part of an update) is apparently not frequent.