Update git submodules

Update git submodules

* Update docs/submodules/compass4nfv from branch 'stable/euphrates'
  - Update the Euphrates docs for kubernetes scenario

    JIRA: -

    In the Euphrates release, compass has supported kubernates
    deployment now. However, there is no k8s related description
    in docs of compass4nfv. So we add k8s related description in
    this patch including the k8s architeture, k8s networking in
    Compass, k8s virtual deployment and k8s bare metel deployment.

    Change-Id: I3bea3ae06b1c73076ba44d10caf89602928b7021
    Signed-off-by: Yifei Xue <xueyifei@huawei.com>
    (cherry picked from commit 4f90858ffbe3e566f30f8bf58309d28989212d0e)