ARP patch implementation

Uses basic ebtables manager and minimal changes to existing
iptables code.

The ebtables manager is based on the patch provided
here: https://review.openstack.org/#/c/70067/

However, this is simplified by not including the refactoring
of the iptables related code. We are only using the ebtables
manager to add ARP filtering rules, nothing else.

Change-Id: Ibc218d6536e86a1a3730ead1f15c5d2a9b7382d6