- 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
* new package "DSRC" (bioinformatics)
* remove uncommented line
* get rid of unnecessary import
* convert to MakefilePackage class
* get rid of make() in install phase, remove spaces
* make flake8 happy!