refactor: running and killing ros2 processes

[jmatejcz]

Purpose

Current implementation of running and shutting down ros2 stack gives little control from python level.

Besides that i refactored simulation config logic as it was not best suited for current code.
the SimulationConfig contained both entities which is required for scene setup and settings for simulation and robotic stack which are needed only when launching. This was not the cleanest by itself but also resulted in confusing configurations:

• Every single Scenario needed entites but had also all the configuration for simulation
• The ifs to run simulation were checked at every scenario

Proposed Changes

Introduced Ros2LaunchManager which manages the launching and shutting down of ros nodes via LaunchService object from ros2 api.
Field robotic_stack_command removed from o3de_config as it was weird that user need to provide this. Now it is LaunchDescription is assigned to benchmarks.

Refactored Simulation config that into:

• SimulationConfig that retained simulation configs
• SceneConfig - with entites

O3DExROS2SimulationConfig is now without robotic_stack_command field as it no longer needed

Issues

#571

Testing

1. Remove robotic_stack_command from your o3de_config.yaml
2. Run python src/rai_bench/rai_bench/examples/test_models.py
   with settings:

 models_name = ["qwen2.5:7b", "llama3.2"]
    vendors = ["ollama", "ollama"]
    benchmarks = ["manipulation_o3de"]
    extra_tool_calls = [5]
    repeats = 1

3. Check if nodes are properly closed after finish:

ros2 node list

[jmatejcz]

I' m not sure where to put Ros2LaunchManager, for its in rai_sim/launch_manager.py

[maciejmajek]

Please rename Ros2LaunchManager to ROS2LaunchManager, other than that LGTM and GJ