Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "xci: Add main playbooks and files"
  - xci: Add main playbooks and files

    This patch adds the main/common playbooks, files, and templates to
    be used for all flavors.

    The provisioning and OpenStack installation process will be as below
    - provision VMs for flavor using bifrost
    - once the VMs are provisioned, configure-localhost.yml playbook will
    be run, preparing the localhost in order to ensure the right playbooks
    (configure-opnfvhost.yml and configure-targethosts.yml), inventory files
    and var files are in place before we proceed with configuring opnfv host.
    - after getting the right files for the flavor, opnfv host will be
    configured using configure-opnfvhost.yml playbook.
    - finally, the target hosts will be configured.
    - once the above process is completed, openstack-ansible playbooks will
    be run, setting up hosts, infrastructure and OpenStack.

    Change-Id: I6e08b2cfdab9627f765e6fc414917b09f953cab2
    Signed-off-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>