BaseEnv currently is missing unit tests. To address this problem a
initial test class is create using the unittest framework. This test
checks the initialization of an empty BaseEnv for both cpu and cuda
devices. It also checks for proper dimension of action and observation
manager terms.

Finally this adds James Tigue to the contributor list.

- Adds Unit Test

- [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 run all the tests with `./orbit.sh --test` and they pass
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there