Read kernel module names from files in
/etc/postmarketos-mkinitfs/modules and print out which modules are
required by which of these files as the initramfs gets generated. Put
the default modules into a new 00-default.modules. This allows mkinitfs
hooks to add modules to the initramfs.
Parse the modules from a file similar to modules-load.d, with commented
lines and empty lines ignored. Add a simple test script for that and run
it in check().
