[[inputs.vsphere]] to get VM snapshot information

### Use Case

Currently using [[inputs.vsphere]] to get data from vSphere and output them to influxDB using [[outputs.influxdb_v2]].
Then using Grafana to visualise the data. As far as I can see, currently, no metric(s) get VM snapshot data.
This feature request is to see if it's possible to pull VM snapshot information via the [[inputs.vsphere]] plug-in, so this information can be visualised via Grafana.

### Expected behavior

VM snapshot data is collected via the [[inputs.vsphere]] plug-in

### Actual behavior

Currently this not happening

### Additional info

Telegraf version 1.32.1
InfluxDB version 2.7.10
vSphere vCenter version 8.0.2.00200

The request is similar to #7741, but I'm not looking for specific storage usage, only to see if a snapshot exists and the age or the time the snapshot was created.

Start at the inputs.vsphere plugin entry point and review how it currently collects VM metrics, then check the vSphere API for snapshot existence and creation-time fields. Define the resulting snapshot metrics and verify that they are emitted for VMs with and without snapshots and can be visualized through the existing InfluxDB and Grafana flow.

Written by the indexing model from the issue text.