[Feature]: Proper launch routine

[vinzenzm]

Description

Carla allows for ros agents to initialize before the simulation is run.

Additionally, ROS-based agents must communicate to the Leadeboard when the stack initialization is finished. This communication should be done by publishing in the following topic /carla/hero/status std_msgs/Bool.
https://leaderboard.carla.org/get_started/

Currently this status "ok" message is published as soon as acting vehicle controller node starts up. Different sub-components of our code do however need more time than this to initialize. E.g. #272 (Perception loading models).

We could define an initialization checklist, which waits for all components to be properly initialized before sending this status ok.
This could be done adding a topic onto which all initialized components have to publish. If a message from all components was received we send the carla ok status to start the run.

Effort estimate

7

Definition of Done

• Define an initialization sequence and protocol
• Implement said protocoll