Instead of hard-coding a list of binaries to include in the dracut
ramdisk, use the existing binary-deps.d functionality to provide a
list. This will allow other ramdisks (such as discovery) to add
the binaries they need.
Change-Id: Ib7ffa15e08db1cc45e93a8f2a5c01369772c93ff
In preparation for enabling Dracut-based ramdisks, this change
factors out functionality that is common to both busybox and Dracut
ramdisks. Said functionality is moved to a ramdisk-base element
which is added as a dependency of the ramdisk element. ramdisk now
only contains the functionality specific to building busybox-based
ramdisks.
bp tripleo-juno-dracut-ramdisks
Change-Id: Iad2907c8be491c88727d87ed5e5a720e5beb66c3