* vmware_host: add reconnect and add_or_reconnect states
Add "reconnect" and "add_or_reconnect" choices for "state".
* reconnect: reconnect an esxi to a vcenter (imply it is present).
* add_or_reconnect: do the same but add the esxi if absent.
Also:
* tag the cluster_name as required (because it is).
* tag esxi_username and esxi_password as not required because
they aren't when the esxi isn't added.
* vmware_host: add + prepare/document integration tests
vmware_host module
Add integration test for the add part of "add_or_reconnect" state.
Prepare and document integration tests for the reconnect part
of "add_or_reconnect" state and "reconnect" and "absent" states.
Currently we can't test those states as ReconnectHost_Task (for
"reconnect") and EnterMaintenanceMode_Task (for "absent") aren't
implemented yet in vcsim (from vmware/govmomi)
29bed12cdd