- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
* Added a package for the MDAnalysis toolkit.
* Added the dependency on setuptools.
* Added the rest of the dependencies to the py-mdanalysis package. Also
added the griddataformats and seaborn packages to satisfy requirements.
* Removed seaborn package since it has been recently added.
* Fixed flake8 error
* Removed inadvertent commits.
* Cleaned up reviewers feedback.
