Similarly to ofono/phonesim allow tests to be skipped if wpa_supplicant
is not found on the system.
This required some changes to DPP/P2P where Wpas() should be called first
since this can now throw a SkipTest exception.
The Wpas class was also made to allow __del__ to be called without
throwing additional exceptions in case wpa_supplicant was not found.
Make sure we wipe the leases file both for server and client, so that
dhclient doesn't try to re-use leases from previous tests (should really
happen) and waste time waiting for a reply. Extend the timeout from 1s
to 5s, sometimes it takes dhclient 1s just to start. Disable verbose
mode if not needed to avoid dhclient stalling if the pipe is not being
read.
With various versions of wpa_supplicant tested, after an IWD GO tears
the group down, the wpa_supplicant P2P client will not immediately
signal that the group has disappeared but will at least wait for the
lost beacon signal, wait some more and try reconnecting and all that
takes it 10s or a little longer. Possibly sending Deauthenticate frames
to clients first would improve this.
