Documentation/integrations: add 'networking-vpp'
- [Gru](https://github.com/dnaeon/gru) - Orchestration made easy with Go
- [Vitess](http://vitess.io/) - Vitess is a database clustering system for horizontal scaling of MySQL.
- [lclarkmichalek/etcdhcp](https://github.com/lclarkmichalek/etcdhcp) - DHCP server that uses etcd for persistence and coordination.
+- [openstack/networking-vpp](https://github.com/openstack/networking-vpp) - A networking driver that programs the [FD.io VPP dataplane](https://wiki.fd.io/view/VPP) to provide [OpenStack](https://www.openstack.org/) cloud virtual networking
