[FEA] Allow configuring a subset of nodes in a certain mode.

Start with the YAML system-modes configuration in the issue and reproduce the behavior using the two ros2 service calls for /actuation/change_state. Trace how partial mode mappings are applied to lifecycle nodes. Done means a mode can configure only its listed node subset while preserving the other nodes' appropriate states, with the left manipulator reaching active in the provided example.

Hi, first of all I want to say this is a great project to manage lifecycle nodes!

There'a a need to config the lifecycle state of only a subset of nodes in one mode, but config another subset of nodes in other modes.

Let's say, can the following config work? (Currently I don't need the extra parameter-based modes either)

SHM file

# system modes example
---

actuation:
  ros__parameters:
    type: system
    parts:
      drive_base
      left/manipulator
      right/manipulator
    modes:
      __DEFAULT__:
        drive_base: active.__DEFAULT__
        left/manipulator: inactive.__DEFAULT__
        right/manipulator: inactive.__DEFAULT__
      LEFT:
        # drive_base: active.__DEFAULT__
        left/manipulator: active.__DEFAULT__
        # right/manipulsator: inactive.__DEFAULT__
      RIGHT:
        # drive_base: active.__DEFAULT__
        # left/manipulator: inactive.__DEFAULT__
        right/manipulator: active.__DEFAULT__


left/manipulator:
  ros__parameters:
    type: node
    modes:
      __DEFAULT__:
        ros__parameters:
          max_torque: 0.1

drive_base:
  ros__parameters:
    type: node
    modes:
      __DEFAULT__:
        ros__parameters:
          max_speed: 0.1
          controller: PID

right/manipulator:
  ros__parameters:
    type: node
    modes:
      __DEFAULT__:
        ros__parameters:
          max_torque: 0.11

EDIT, the step of reproduce has been updated @ralph-lange

step to reproduce

time ros2 service call /actuation/change_state lifecycle_msgs/ChangeState "{transition: {id: 1, label: configure}}"
time ros2 service call /actuation/change_state lifecycle_msgs/ChangeState "{transition: {id: 3, label: activate}}"

expected

the lefe manipulator should be in active

actual