tests: Add new fchosttest tests for management of a vHBA

tests: Add new fchosttest tests for management of a vHBA

Add a test that will mimic creation and destruction of a vHBA
by using node device XML. The design will allow for testing the
multiple mechanisms.

The first test uses just <parent> in the node device XML. This is
somewhat similar to the existing objecteventtest, except that this
test will not provide input wwnn/wwpn's (similar to how the process
is described for the the libvirt wiki).

This requires mocking the virRandomGenerateWWN since parsing the
input XML (virNodeDevCapSCSIHostParseXML) requires either a provided
wwnn/wwpn in the XML or the ability to randomly generate the wwnn/wwpn.