Draft: main/postmarketos-base: stop replacing the default sudoers file

mkinitfs_functions.sh in postmarketos-mkinitfs uses sudo, so make sure we always have it available no matter what happens in other packages

sudo by default also checks drop-in files in /etc/sudoers.d, so let's use that for the 1 pmOS specific configuration (making everybody in the wheel group allowed to use sudo) rather than overwriting the default sudo configuration