Start implementing a tpm2-initramfs-tool based approach.
This requires a bit of an odd transition as the PCR 7 is likely
to change between the install phase and the boot phase, so
we have to select different PCRs, but that requires
an argument to pass that crypttab does not support.
Ubuntu 22.04 makes some changes, notably removing the
custom-installation hooks.
Change to injecting our modifications more directly to where the
custom-installation hooks used to be.
Jarrod Johnson