CSIT-748 vnf-agent integration

CSIT-773 Implement RF keywords for k8s

- Implementation of Test Suite Setup for Ligato vnf-agent testing
- Implementation of KubernetesUtil for controlling kubectl
- Yaml templates for L2XC topology with 1cswitch and 1cnf
- Yaml templates for L2BD topology with 1cswitch and 1cnf
- ligato bootstrap script for creating vnf-agent image

Change-Id: Iebefde0eb984a27a0afcdf29fe549ca4edf8a61e
Signed-off-by: Peter Mikus <pmikus@cisco.com>
(cherry picked from commit 9a261ea61549fc6a5c23369d2e236b002dc35038)