Support seeding of Dialogs

Related BZ:
https://bugzilla.redhat.com/show_bug.cgi?id=1155806
Move MiqDialog yaml seed files to product/dialogs/miq_dialogs

Related BZ:
https://bugzilla.redhat.com/show_bug.cgi?id=1155806
Refactor spec to use fixture file and seed MiqRegion

Related BZ:
https://bugzilla.redhat.com/show_bug.cgi?id=1155806
Merge pull request #917 from eclarizio/seed_service_dialogs

Support seeding of Dialogs