[tc][neutron] Use Kea insted of Dibbler for IPv6 PD

Hi, In Neutron we have a bug (see [1]) that states Dibbler is concluded (see [2]), and the developer of Dibbler suggests using Kea (see [3]) instead. Before we start checking technical things first thing is that Kea is MPL2.0 licensed (see [4]) and not sure if we can pull that as dependency to Openstack. Kea is an ISC project so looks safe, but I am not familiar with these legal things. How can we check and be sure? [1] https://bugs.launchpad.net/neutron/+bug/1916428 [2] https://github.com/tomaszmrugalski/dibbler#project-status [3] https://gitlab.isc.org/isc-projects/kea [4] https://www.isc.org/kea/ Thanks in advance Lajos Katona (lajoskatona)