Dynamic Obstacle Loading & Build Cleanup

• Adds model for default obstacle shelf
• Now spawns obstacle based on model name in model request
• Default assets from Unity HDRP tutorial were removed

Training & Arena Unity-Rosnav Integration

This release includes full support for training via RGBD as well as integration with the master branch in arena-rosnav

Pedestrian Models

This release adds the latest pedestrian models with different animation for @ddiaz-0.

Window Mode Support

• Build is started in windowed mode
• Support for cursor defocussing and refocussing

Core Functionalities for Unity Simulator

This first release offers the core features in the Arena-Rosnav framework.
The simulator support:

• Dynamic loading of robots
• Laser scan for robots and their dynamic configuration
• Publishing for robot on all required topics (tf, odom, scan)
• Movement of robots according to the Arena-Rosnav navstack
• Dynamic loading of maps
• Loading of pedestrians and obstacles (currently no model, only basic cubes)
• Movement of pedestrians according to pedsim