Follow busybox upgrade to 1.22

Just rename the bbappend recipe, our config is compatible with both
1.21 and 1.22 versions.
Add dyplo recipes
Prevent alsa-utils from dragging in udev

alsa-utils doesn't check the preferred provider, so override with a
bbappend to prevent it creating a udev dependency.
README: Emphasize the use of DISTRO=tiny for my-image