Update git submodules

Update git submodules

* Update docs/submodules/sdc/sdc-distribution-client.git from branch 'master'
  to 8d66fe815808883f383270eed43fb699c7449631
  - Migrate sdc-sdc-distribution-client docs

    Merging this will create
    https://onap-sdc-sdc-distribution-client.readthedocs.io
    This build will run in parallel
    to the current docs generation method
    until we are ready to cut over.

    Issue-ID: CIMAN-364
    Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
    Change-Id: I55eae1febe5ec87628e963920b091b3955db56f3