# Description

Adds `add_app_launcher_args` function to the `AppLauncher` class, which
can be used to add AppLauncher-specific arguments to an existing
ArgumentParser instance.

Because everything we pass is then passed to SimulationApp as a config,
the MR also adds the `check_config()` function. This compares the key
values of a dict and raises a ValueError in the following cases:
* if they have a key reserved for a SimulationApp config parameter but
incorrect value types
* if the value type is correct, it informs the user if a dict item they
passed will be interpreted as a SimulationApp config parameter.
Non-SimulationApp relevant keys are cleaned from the dict before it is
passed to SimulationApp.

Also separated out the giant `AppLauncher.__init__` function into a few
sub-functions to make things more readable.

## Type of change

- New feature (non-breaking change which adds functionality)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] 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

---------
Signed-off-by: AutonomousHansen <50837800+AutonomousHansen@users.noreply.github.com>
Co-authored-by: Mayank Mittal <mittalma@leggedrobotics.com>