OPENDJ-1870 CR-6581 Update BackupManager to generic tool
Move pluggable.BackupManager to util.BackupManager
Make util.BackupManager generic to handle any backup
Add Backupable interface , to represent an entity that can be
backed up
Replace createBackup(), restoreBackup() and removeBackup()
implementations by call to BackupManager in several classes:
- jeb.BackupManager
- SchemaBackend
- TaskBackend
- ConfigFileHandler
Add new test case BackupManagerTestCase
Update properties files : backend, jeb, utility