vpp-swan: Add scripts for testing

Added scripts to reparing setups for testing

To prepare and run containers:
sudo ./extras/strongswan/vpp_sswan/docker/run.sh prepare_containers

To prepare setups:
sudo ./extras/strongswan/vpp_sswan/docker/run.sh config

To clean-up settups:
sudo ./extras/strongswan/vpp_sswan/docker/run.sh clean

To deleted all containers and images in Docker:
sudo ./extras/strongswan/vpp_sswan/docker/run.sh deleted

Type: feature
Signed-off-by: Gabriel Oginski <gabrielx.oginski@intel.com>
Change-Id: I77f01c0419dccc95f610046c8552ae825f2c7e12