add guix.scm to declare package definition
description https://codeberg.org/guix/cuirass/src/branch/main/build-aux/guix/cuirass-package.scm
https://github.com/ekaitz-zarraga/reminder/blob/master/guix.scm
human iditer-vitae-245priority0id15cedcb7-b147-46a4-a58e-5c432784192d