implement vsan object health check

[datamuc]

In the GUI we can see:

Cluster->Monitor->Skyline Health->vsan object health

We can access that stuff with a stupid addon to pyVmomi:

https://developer.vmware.com/web/sdk/8.0/vsan-python

• get VsanObjectOverallHealth of the Cluster
• analyze the objectHealthDetail property
• create a check result based on vim.host.VsanObjectHealth.VsanObjectHealthState of the objectHealthDetails

Here is an in depth explanation of VsanObjectHealthState:

https://kb.vmware.com/s/article/2108319

[datamuc]

First proposal implmented with 0e7bff4