DG healthchecks

1. added DG healthcheck - separate one for primary and secondary
2. if DG secondary is out of sync, backups will run on primary too
3. if DG secondary is out of sync, log file will have a warning about
this
4. moving DG logic from main script to the subs script.
5. CROSSCHECK ARCHIVELOG ALL completed after - there is was an unicode
chracter. Fixed.