Add Vagrantfile for local testing.

Add Vagrantfile for local testing.

Vagrantfile contains 3 VMs as of now, 2 DUTs 1 TG, with these notes:
 - login is csit/csit
 - by default provision script installs all deb packages from the dir
    where Vagrantfile is
 - developed for, and only tested on vbox (someone can pick up vmware)
 - All nodes have 1 shared mgmt network: 192.168.255.0/24
 - hosts have these IP addresses in host-only network
    TG : 192.168.255.100
    DUT1 : 192.168.255.101
    DUT2 : 192.168.255.102
 - script created to download MAC address information
 - PCI addresses are always the same for vbox (not sure about vmware)

HOWTO (will create a wiki page once one is created for CSIT project):
 - copy Vagrantfile to separate dir on host
 - vagrant up --parallel
    sit-back-and-relax
 - from VM that has access to the same host-only network (192.168.255.0 above)
    - copy your ssh-key to csit@192.168.255.{101,102,250} using
        ssh-copy-id
    - cd ${csit_dir}
    - virtualenv & pip as in README
    - export PYTHONPATH=${csit_dir}
    - resources/tools/topology/update_topology.py -v -f
        -o topologies/available/vagrant_pci.yaml \
        topologies/available/vagrant.yaml
    - pybot -L TRACE \
        -v TOPOLOGY_PATH:topologies/available/vagrant_pci.yaml -s \
        "ipv4" tests
    - see tests results

Change-Id: Ic27626605a9c820bca977b38f4e8ca37d1504ff5
Signed-off-by: Stefan Kobza <skobza@cisco.com>