Environments synchronization

Because of some user activity devops database could
contain outdated data. The review adds new 'sync' command
that allows to synchronize devops database and
libvirt domains.
Synchronization include:
- Undefining domains that devops do not know about
- Removing records from devops database if
there are no such domains

Change-Id: I2331174a60f581f24219ae124da1cf5fe4ca3f09