Add the `vmware/scenario/vcenter_only` alias to be able to identify the
vmware test roles that can be tested with just on vcenter instance.
Also, add a check to be sure we don't try to attach ESXi hosts if none
has been defined.
* add vmware_evc_mode module
* alter result message for absent/absent
* Apply suggestions from code review
Co-Authored-By: CastawayEGR <36353334+CastawayEGR@users.noreply.github.com>
* add idempotency test
* change result dict to evc_mode_msg
* refactor to use pyvmomi class
* fix update to only process task on update
* minimize update code
* add single quotes around vars to match other code
* pass datacenter to cluster find
* add check_mode to disable test
