[Metricbeat] VMware mapping with Cluster, Host, Datastore & Network.

**Describe the enhancement:**
To enhance data mapping among data collected from vsphere module.
**Describe a specific use case for the enhancement or feature:**
1. To be able to see a clear relationship between the host, datastore and VMware ESXi.
2. Clear information of which datastore resides in which ESXi host. Currently, we see such mapping available only for Virtual machines and ESXi hosts.
3. It is also good to have the cluster name under which the ESXi is part of. This information is currently not fetched by metricbeat.