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

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

This is blocked on https://gitlab.alpinelinux.org/alpine/apk-tools/-/issues/10747 sadly, upstream plans to fix it with apk-tools v3.