Enable user to collect all available VMFS datastores under a given vSphere Cluster

[rahman-lb]

This PR will enable user to know all available datastores under a given cluster. In many cases end-user of the RunCommand wants to know the existing datastore and its capacity vs available space. This PR also introduce a change to existing Dismount-datastore for NVMe/TCP devices, current behavior is PRESERVED for scsi devices, and NVMe/TCP devices are not detached after Dismount command similar to other VMware API and vSpher WebUI.

The changes in this PR are as follows:

• Get all available datastores under a given vSphere Cluster.
• Dismount will not detach NVMe/TCP devices from ESXi host similar to VMware Unmount using WebIU and mgmt SDK.

I have read the contributor guidelines and have completed the following:

• [x] Formatted the code using VSCode default formatter for PowerShell.
• [x] Tested the code end-to-end against an SDDC.
• [x] Documented the functions using standard PowerShell markup and applied AVSAttribute to newly exported functions.

[rahman-lb]

@srajmohan24

[rahman-lb]

@srajmohan24