This commit fixes the aggregation of multiple host variables values.
Let's say SNow returns something like this:
```
{'u_name': 'First_app', 'u_parent': 'tomcat_aqwidmvs', 'sys_id': 'a7dc8d0633a8d210392d0e570e5c7bb4', 'u_child': 'i101', 'u_level': '1', 'u_child.name': 'i101', 'u_child.ip_address': '10.1.0.101', 'u_parent.support_group': 'Application Development', 'u_parent.name': 'tomcat_aqwidmvs'}
{'u_name': 'Second app', 'u_parent': 'tomcat_pxgnodig', 'sys_id': 'f9fc8d0633a8d210392d0e570e5c7bff', 'u_child': 'i101', 'u_level': '1', 'u_child.name': 'i101', 'u_child.ip_address': '10.1.0.101', 'u_parent.support_group': 'Application Development', 'u_parent.name': 'tomcat_pxgnodig'}
```
For the same host, we have two records with different values: u_parent,
u_parent.name, u_parent.support_group, u_parent.name.

This change will aggreate these values as follows:
```
all:
  children:
    ungrouped:
      hosts:
        i101:
          sys_id: a7dc8d0633a8d210392d0e570e5c7bb4
          u_child:
          - ip_address: 10.1.0.101
            name: i101
          u_level: '1'
          u_parent:
          - name: tomcat_aqwidmvs
            support_group: Application Development
            u_parent: tomcat_aqwidmvs
          - name: tomcat_pxgnodig
            support_group: Application Development
            u_parent: tomcat_pxgnodig
          u_type: active
```

To enable this aggregation, the inventory must have:
```
experimental_aggregation: true
```