To ease the addition and removal of packages, some rules were added to
deal with those specially.
I still need to figure out how to stop repeating myself when linking and
unlinking unconventional packages (such as `scripts`).
Instead of running `install.sh` to link all my packages, I split the
configuration into its CLI components and packages that need a Xorg
display server set-up.
This uses the `bootstrap.sh` script to make sure the needed dependencies
are installed. The `Makefile` can install all the packages or CLI ones
only.