Repo adaptation to cookiecutter-conda-package

This PR adapts the repository so that it works with cookiecutter-conda-package.

[x] Continuous integration
~~[ ] Continuous delivery~~
[x] Run automatic pre-commit hook fixes
[x] Manually change the code to pass the pre-commit hooks' requirements
[x] Manually change the code to pass all D401 and D402
[x] Create tests directory in the root directory to match the cookiecutter template
[x] Remove old tests
[x] Move packages to src dir
[x] Remove superseded pylint directives
[x] Adapt repository to the docs template of cookiecutter
[x] Configure pyproject.toml and remove old setup.cfg and setup.py
[x] Create new conda environment.yml
[x] Update README.md
[x] Add pre-commit-jupyter to the pre-commit-hooks so as to remove kernel metadata
[x] Renamed pynemo as pybdy

Notes:

type-check was removed from the "default" target in the Makefile to avoid running type checks by default (code has no type hints)
the type checking procedure is also commented in the CI/CD workflow
the CI workflow uses Python 3.9. Other versions can be added to the matrix, but for the CI workflow to work with those the python=3.9 line must be removed from the environment.yml file
currently delivery to PyPI is commented in the workflow
the following occurrences of pynemo were not renamed as pybdy (see Issue #103):
- The url http://pynemo.readthedocs.io/en/latest/index.html (pyproject.toml, README.me)
- pynemo references in docs/source/example.rst (these instructions need an update)
- URLs containing pynemo in inputs/src_date_remote.ncl, inputs/namelist_remote.bdy, dosc/source/usage, docs/source/installation.rst, docs/source/examples.rst, docs/source/nmcl_generator_usage.rst

NOC-MSM / pyBDY