Update git submodules

Update git submodules

* Update docs/submodules/kvmfornfv from branch 'stable/danube'
  - Update documentation structure.

    This patch is used to update documentation structure.

    Change-Id: I50d4ef4256ccfc57a0434123e7532a50000582cf
    Co-Authored by:Srinivas <srinivas.atmakuri@tcs.com>
    Co-Authored by:RajithaY<rajithax.yerrumsetty@intel.com>
    Co-Authored by:shravani paladugula <shravanix.paladugula@intel.com>
    Co-Authored by:Navya Bathula <navyax.bathula@intel.com>
    Signed-off-by: Gundarapu Kalyan Reddy <reddyx.gundarapu@intel.com>
    (cherry picked from commit f1f3cc27f23bdde81c37d8142d4288d811bd5e45)