[ROS2] Make Planning or Execution Optional for MoveTo

[Amal Nanavati]

Currently, the MoveTo behavior executes both planning and execution. However, there might be cases where we want to do multi-stage planning (e.g., plan the movement to the food and the movement within the food) before executing them both. To enable something like this, MoveTo must have the option to either plan or execute or both.

• If it is set to just plan, it should write the trajectory to blackboard.
• If it is set to just execute, it should read the trajectory from the blackboard.
• If it set to do both, it doesn't read or write the trajectory to/from the blackboard.

[Amal Nanavati]

Addressed with #115