Get MAC addresses and use them as network interface id-s.
Support both nova and libvirt driver.
get_nics returns list of dictionaries so that it can be extended
to return more attributes, e.g., IP addresses.
In the returned dictionary I have duplicated 'id' and 'mac' in
case different id strategy is necessary in future (maybe this is
premature).
Story: 2003018
Task: 23038
Change-Id: I3787824ffdea3ade5419fecbe6e643cf5f432e9b
Co-Authored-By: Aija Jaunteva <code@clusums.eu>
