A service that has no parent but is unreachable, has a host
which marks it as such. In other words, an implicit dependency.
As long as we don't fully support implicit dependencies,
such a service must be shown as root problem. Otherwise,
the message about insufficient access rights is shown.
- Disable the default sorting for the `$hasDependencyNode` and UnreachableParent's `$rootQuery`, as sort is not required here
and triggers an error, because the sort columns are not retrieved.
A node is responsible if:
* it's a host which is reachable but has a problem
* it's a service which is reachable but has a problem
* it's a redundancy group which is reachable but has failed
