Fix NMS-6580: Security: downloadReport allow download and view any file in filesystem
Restrict to files in the Reportd storage directory (default OPENNMS_HOME/share/reports)
Clean up imports
Merge remote-tracking branch 'origin/1.12'

Conflicts:
	opennms-webapp/src/main/java/org/opennms/web/controller/DownloadReportController.java