- 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
* gtkorvo-atl: atl library from gtkorvo
* gtkorvo-dill: dill library from gtkorvo
* gtkorvo-cercs-env: cercs_env library from gtkorvo
* gtkorvo-enet: Enet networking library from gtkorvo
* libffs: FFS middleware communication library from GTKorvo
* libevpath: EVPath high performance communication library from GTKorvo
* gtkorvo-cercs-env: Added homepage and removed function configure_args
* gtkorvo-cercs-env: Re-add of accidental removal of cmake_args function in previous commit
* gtkorvo-enet: Removed configure_args since unused