virsh: Split cmds for domain monitoring from virsh.c

virsh: Split cmds for domain monitoring from virsh.c

This splits commands commands to monitor domain status into
virsh-domain-monitor.c. The helpers not for common use are moved too.
Standard copyright is added.

* tools/virsh.c:
  - Remove commands for domain monitoring group and a few helpers (
    vshDomainIOErrorToString, vshGetDomainDescription,
    vshDomainControlStateToString, vshDomainStateToString) not for
    common use.
  - Remove (incldue "intprops.h").

* tools/virsh-domain-monitor.c:
  - New file, filled with commands of domain monitor group.
  - Add "intprops.h".

* cfg.mk:
  - Skip strcase checking for virsh-domain-monitor.c
  - Skip to check config.h including for virsh-domain-monitor.c

* po/POTFILES.in
  - Add virsh-domain-monitor.c