- 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
* r-igraph: find old packages in the archive
Fixes#6104.
* r-irlba: find old packages in the archive
Fixes#6101.
* r-lazyeval: find old packages in the archive
Fixes#6102.
* packages: set list_url for all packages hosted on CRAN
* packages: consistently use the CRAN archive URLs
* Add package for r-ada, update r-rpart version
Adds a package for r-ada.
Update the version for r-rpart because the previous version is
no longer at that URL. The previous version *is* in the Archive,
but list_url does not seem to be able to find it.
* Clean up FIXMEs (blush)
