Remove DKMS machinery

We can't use DKMS to load out-of-tree modules into our kernel by default
without incurring negative consequences we don't want to deal with.
Remove the machinery for now since we won't be using it.

Reverts 7f3f03a19f

Related to #3

mkosi.conf.d/00-packages-core.conf

@@ -16,7 +16,6 @@ Packages=
     kmod
     kmscon # modern userspace getty and virtual terminal replacement
     linux-firmware
-    linux-headers # For DKMS
     linux # It's the kernel!
     plymouth
     realtime-privileges # `realtime` group and realtime privileges for processes using it

mkosi.extra/usr/lib/rebuild-efi

@@ -18,12 +18,6 @@ if [ -z "$kernel_version" ]; then
   exit 1
 fi
 
-# Ensure all DKMS modules are built for this kernel before we generate the initramfs
-if ! dkms autoinstall -k "$kernel_version"; then
-  echo "Error: DKMS autoinstall failed" >&2
-  exit 1
-fi
-
 # NOTE: plymouth MUST be after systemd as per the wiki!
 cat <<- EOF > mkinitcpio.conf
 MODULES=(overlay)

mkosi.finalize.d/40-core.sh.chroot

@@ -120,12 +120,6 @@ rm -rf /boot/*
 ## Don't expose any X11 sessions; we're all-in on Wayland.
 rm -rf /usr/share/xsessions/
 
-## Get rid of the beefy Kernel Headers as DKMS happens at build time and after that is useless
-rm -rf \
-  /usr/lib/modules/*/build \
-  /usr/lib/modules/*/vdso \
-  /usr/src/*
-
 # Prevent tuned from messing with the vm.swappiness parameter we already set
 sed --in-place 's|^vm.swappiness.*||' /usr/lib/tuned/profiles/*/*