Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Update CVP Docker Compose Configuration

    - Uses extra files config.env, vhost.env to hold environment variables
      for docker configuration.

    - Provides samples for these config that can be copied and modified to
      fit deployment requirements.

    - Updates the docker images to the newest releases.

    Change-Id: Ibe9b8597edfb38940297433708497c244200d0af
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>