Move utils to guix-hpc module.
The current channel layout, using institution names, doesn't help to categorize new software. This is a first step to switch to a more consensual way of organisation.
- guix-hpc/packages/emacs-xyz.scm: Rename utils/emacs-xyz.scm.
- guix-hpc/packages/lsp.scm: Rename utils/lsp.scm.
- guix-hpc/packages/mumps-variants.scm: Rename utils/mumps-variants.scm.
- guix-hpc/packages/python-science.scm: Rename utils/python-science.scm.
- guix-hpc/packages/utils.scm: Rename utils/utils.scm.
- cea/pdi.scm: Update module import.
- inria/datamove.scm: Update module import.
- inria/melissa.scm: Update module import.