- 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
* transabyss: new package and dependencies
* fixed build deps in igraph and version conflict spec in abyss
* fixed versioning stuff and package structure
* fixed dep type
* fixing dep type for real this time
