* guix/import/opam.scm: Update importer for opam 2. * tests/opam.scm: Update tests for the opam 2 importer.
* guix/scripts/import.scm (importers): Add opam. * guix/scripts/import/opam.scm: New file. * guix/import/opam.scm: New file. * tests/opam.scm: New file. * Makefile.am: Add them. * doc/guix.texi (Invoking guix import): Document it.