Add lifecycle subscriber to lifecycle nodes

[carmiac]

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This adds a LifecycleSubscriber class to lifecycle nodes. In general, it is a mirror of LifecyclePublisher scheme, both for determining whether to process messages and in the factory methods.

There is a linked PR that provides a demo and test node.

[ros-discourse]

This pull request has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/lifecycle-node-improvements/32706/1

[dadaroce]

Any progress on this? looks like a really useful feature 😄

[fujitatomoya]

AFAIK, no progress. @carmiac are you going to work on this?

i think what we need to do is,

• add lifecycle subscriber test in this PR.
• add TODO for Hold onto the data that arrives before activation, and deliver that on activation, see https://github.com/ros2/rclcpp/pull/2254#discussion_r1290505034
• and probably we can add some explanation for https://docs.ros.org/en/rolling/Tutorials/Demos/Managed-Nodes.html?