Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Refactor core VNF class"
  - Refactor core VNF class

    - Simplify processing
    - Implement run method to inherit testcase methods
    - Add unit tests
    - Fix all pylint issues

    It also obliges vnf and its uts to be rated 10/10 by pylint.

    JIRA: FUNCTEST-830

    Co-Authored-By: Cédric Ollivier <cedric.ollivier@orange.com>
    Change-Id: I8dd24eea55089277c9e5b2b51fb14dc377f2fcaf
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>