Optional MAC address and other changes

Optional MAC address and other changes

The MAC address of the dataplane interfaces in the environment file is
now optional. If not specified, the HW MAC address of that interface
will be used. When using l2 tests, the parameter will be needed anyway
and the test will fail if the MAC address is not specified.
Starting from DPDK 20.11, the EAL --pci-whitelist parameter changed into
--allow. We are now checking the DPDK version of the PROX instance to
determine which parameter to use.
For pods using cgroup v2, we are now using a different file to determine
the cpuset available to the pod.

Signed-off-by: Luc Provoost <luc.provoost@gmail.com>
Change-Id: I7a88458406b9ae3c8cae9c583cc37121d40c5073