Add drone_gymkhana.world from RoboticsAcademy exercises drone_gymkhana for testing drone 3d control

[damodardatta]

Need to do the following tasks first before proceeding to add new environments for testing the 3D control of drones:

• Prepare documentation and Instructions for installing drone launch files in the latest version (Noetic) of BehaviorMetrics.
• Verify if the previous implementations of brain models are still working for the current version.
• Finally, add Drone gymkhana, a world that requires 3D control rather than Circuit, which can be just navigated with 2D control and commands.

[sergiopaniego]

Thanks for opening the issue.
You can divide the tasks in several small pull requests, so their easier to merge.

[damodardatta]

Added instructions for launching in BehaviorMetrics #612