RFE: Add support of fence-scsi for RHEL 8 cluster running in vCenter 7/8 with VMDK shared disk

+++ This bug was initially created as a clone of Bug #1860897 +++

Description of problem:

Currently Red Hat doesn't support usage of fence_scsi and fence_mpath on VMDK devices in VMware environment [1]. However according to [2] VMware added support of SCSI-3 Persistent Reservations (SCSI-3 PR) at the virtual disk (VMDK) level in vCenter 7 (part of vSphere 7 platform):

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Shared VMDK on VMFS6
In vSphere 7, VMware added support for SCSI-3 Persistent Reservations (SCSI-3 PR) at the virtual disk (VMDK) level. What does this mean? You now have the ability to deploy a Windows Server Failover Cluster (WSFC), using shared disks, on VMFS. This is yet another move to reduce the requirement of RDMs for clustered systems. With supported HW, you may now enable support for clustered virtual disks (VMDK) on a specific datastore. Allowing you to migrate off your RDMs to VMFS and regain much of the virtualization benefits lost with RDMs.
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The goal of this bugzilla is to have fence_scsi and fence_mpath tested in vCenter 7 environment with VMDK shared device and deliver official supportability statement.

[1] Support Policies for RHEL High Availability Clusters - fence_scsi and fence_mpath
https://access.redhat.com/articles/3078811

[2] https://storagehub.vmware.com/t/vsphere-7-core-storage/shared-vmdk/

— Additional comment from RHEL Program Management on 2020-07-27 11:37:15 UTC —

Since this bug report was entered in Red Hat Bugzilla, the release flag has been set to ? to ensure that it is properly evaluated for this release.

— Additional comment from RHEL Program Management on 2020-07-27 11:37:15 UTC —

The keyword FutureFeature has been added. If this bug is not a FutureFeature, please remove from the Summary field any strings containing "RFE, rfe, FutureFeature, FEAT, Feat, feat".