[#DCMEEREQ-7 Provide Audit Record Repository]

Added implementation for audit backup service with 3 more configuration
options:
1-enable/disable safeclean
2-backup service poll interval in seconds
3- backup dir url

the new service is integrated with the clean service, when the clean
service attempt to delete a file, it first makes a copy of the file in
the backup dir as .tmp file then the file is renamed to remove the
extension (guaranteeing the backup service exclusive acces to the file
only when it has no extension)

The backup service then scans the directory for files and creates a dir
inside which it creates a zip file for the backed up audits.

Tested with ldap