hosts and services groups, set level
hosts and services groups, set level

Define a group level (from 0 to ...) based upon hostgroup_members and
servicegroup_members properties defined in Shinken hostgroup and
servicegroup objects.
If PR https://github.com/naparuba/shinken/pull/1654 is accepted ... if
not, groups level is 0.

rednach/mod-webui,vizvayu/mod-webui,vizvayu/mod-webui,mohierf/mod-webui,rednach/mod-webui,shinken-monitoring/mod-webui,shinken-monitoring/mod-webui,rednach/mod-webui,mohierf/mod-webui,shinken-monitoring/mod-webui,mohierf/mod-webui