mmc-install: Add more useful packages

This is from a diff with a working system.

Signed-off-by: Sean Cross <xobs@kosagi.com>
novena-image: Set up the recovery kernel

If the kernel has been installed, and if a recovery kernel doesn't already
exist, copy the installed kernel to a recovery location.

This enables the user to boot even when their normal kernel is broken.

Signed-off-by: Sean Cross <xobs@kosagi.com>