Add ncm-xrootd to main pom.xml
Fix ncm-wmsclient description in its specific pom.xml
ncm-xrootd: fix authLibraries handling and work around an exists() flaw
ncm-xrootd: documentation update to reflect current state of the
component
ncm-xrootd: schema adjustments
ncm-xrootd:
 - Federation configuration support added
 - support for instance restart rather than service restart
 - Improve restart logic to avoid unnecessary restart of instances
   after a sysconfig file change
 - Documentation up-to-date with new features