DS-1028: CAS authentication

https://jira.duraspace.org/browse/DS-1028

It is currently failing building. I am leaving this here for ideas and tips on trying to get it working.

[ERROR] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Compilation failure
/home/dspace/dspace-src/dspace-xmlui/src/main/java/org/dspace/app/xmlui/aspect/administrative/eperson/AddEPersonForm.java:[182,25] cannot find symbol
symbol  : variable ConfigurationManager
location: class org.dspace.app.xmlui.aspect.administrative.eperson.AddEPersonForm