System Test for Backup and restore of Fuel Master

Added tests backup feature:
-Accessibility of lrzip archive in /var/backup/fuel/
-Nailgun accessibility after backup
-For base(only master), simle, ha modes.

Added tests restore feature:
-md5sum of specific file before/afrer restore
-Nailgun accessibility after restore
-For base(only master), simle, ha modes.

blueprint system-tests-for-backup-and-restore

Change-Id: I7f9cb8765a89f270d223b516ac70bf87e5bfc53f
Merge "System Test for Backup and restore of Fuel Master"