Fix "invalid parameter domain_internal_suffix" on monitor node (#6477)

leap_platform was modified so the nagios.internal_domains contain the
domain name (with the tld replaced by an "i" for internal), see
https://leap.se/code/issues/6477#note-11.
in order to achieve this the easy way, each host got added a
domain_internal_suffix value, which can be iterated over to get all
nagios.internal_domains.

Because we use `create_resources ( site_nagios::add_host_services,
$nagios_hosts )` in site_nagios::server to deploy the services, the
site_nagios::add_host_services define needs to have a
domain_internal_suffix parameter added.

Change-Id: I6b83b3f291a1a611b5b92d5ba3ed82597a42bba7
Merge branch '6477_fix_invalid_parameter_domain_internal_suffix' into 'develop'

6477 fix invalid parameter domain internal suffix

https://leap.se/code/issues/6477#note-17

See merge request !8