Refactor in infra tag tests

`infrastructure_virtual_machines` is special in that it remembers the last item where you have been so when you click the `Virtual Machines` menu again, it won't get you to the  VM list but rather to the VM where you had been before. This was causing failures in the vm tagging test which was expecting to be on VM list page after the Virtual Machines click. So I used the more specific locators from one level deeper, that also click the accordion - I extended the test the way it now does it separately on VMs and Templates.

I also changed the tag tests to be parametrized to save lines. I also added test for tagging from details.

And to speed things up, I moved the infra provider setup to be module scoped here.
https://github.com/RedHatQE/cfme_tests/pull/1193/