Update git submodules

Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 8c9f2c73f4366ae42ad7e2c1742885b5ad793360
  - decision point API

    ControllerRunnable interface: implemented by controller
    ControllerContext: Controller Context for controller execution
    ControllerPreparable interface:used to setup execution context
    ControllerExecutionBB:controller execution for building block
    ControllerExecutionDE:controller execution for camunda
    Skeleton implementation for APPC controller
    Skeleton implementation for SDNC controller
    Use ControllerExecutionDE for existing PNF configuration.
    Add integration tests for controllerExecutionBB/DE
    Add GenericControllerExecution activity for BuildingBlockExecution based
    Add GenericControllerExecutionDE activity for DelegateExecution based.
    CDS controller to be implemented by SO-CDS generic buildingBlock
    Actor seletion based on ingested metadata

    Issue-ID: SO-2070
    Change-Id: I4020c2ce21468939690e2cef78bbadbfff4bd3e4
    Signed-off-by: eeginux<henry.xie@est.tech>