Add a mechanism for selecting multiple MRM behaviors

[mkuri]

Checklist

• I've read the contribution guidelines.
• I've searched other issues and no duplicate issues were found.
• I've agreed with the maintainers that I can plan this task.

Description

Currently, there is one MRM behavior (e.g., sudden stop) that can be selected on the hazard condition.
(MRM: Minimum Risk Maneuver)

Purpose

Provide a mechanism to select multiple MRM behaviors depending on the hazard state.

Possible approaches

Create intermediate nodes that control MRM behavior, and the emergency handler activates each node according to the hazard state.
MRM behaviors can be added by creating new intermediate nodes.

Definition of done

• There is a mechanism to select MRM behavior
• Emergency stop can be selected for MRM behavior using the above mechanism as before
• Comfortable stop can be selected for MRM behavior using the above mechanism

Other MRM behaviors will be added in the future.