Replace dialog seeding with miq_dialog_host_provision factory.

Marked the one test as no longer pending because although we may not
support host provision from the webservice, the from_ws method is a
valid entry point and through that entry point, host provisioning should
be working.

The confusion comes from the name of the method from_ws, which by name
sounds web-servicey, but really it's just a generic entry point with
parameters. It was written for web services initially, but it's really
just a proper interface method, that could be used by anything. We
should rename that method in a separate commit.

Total time for this spec dropped from 3.47s to 2.4s and we ADDED a test.
WAT