Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Add lesser containers based on Alpine"
  - Add lesser containers based on Alpine

    It splits the full container into:
      - functest-core
      - functest-healthcheck
      - functest-smoke

    Smoke suite is currently partial and will be completed later (it may
    require updates in third party projects).

    Features, components and vnf suites will be integrated in other
    patchsets.

    Change-Id: I635a7fd84cac583c28bb1c82bc6cc9107a39f7ea
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>