This removes all the duplicated code where the interfaces are iterated
and the radio/hostapd instances are created. Instead the two new APIs
are used to get each instance, e.g.:
hapd = HostapdCLI(config='ssid.conf')
radio = hwsim.get_radio('radX')
In the tests that only want to iterate over the hostapd interfaces,
simplify the pattern of walking through the whole wiphy_map tree by
instead using the hostapd_map variable which is already filtered to only
contain hostapd interfaces.
