# Description

This MR does the following:

* Changes the way environment and agent configs are handled. These are
now moved to their respective `env` folder.
* Replaces YAML file with configclasses for rsl_rl library
* Adds examples of other robots for locomotion-velocity task: anymal-b,
unitree-a1, and anymal-d (placeholder)

The new environment folder structure is as follows:

```
my_task (folder)
   |- mdp  (folder where all user's task-specific terms are stored)
   |- config
       |- robot_name_1  (folder)
            |- robot_specific_env_cfg.py
            | agents (folder)
                |- rsl_rl_cfg.py
                |- sb3_cfg.py
                |- ....
            |- __init__.py (register robot-specific tasks)
       |- robot_name_2 (folder)  
   |- my_task_env_cfg.py (base env config)
   |- my_task_env.py (base env -- optional -- should normally use RLEnv)
```

Fixes #142 

## Type of change

- New feature (non-breaking change which adds functionality)
- Breaking change (fix or feature that would cause existing
functionality to not work as expected)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file

---------
Co-authored-by: Nikita Rudin <nrudin@nvidia.com>