When zkey is properly setup, we do not invoke cryptsetup luksFormat
ourselves. Instead we lean on zkey to invoke cryptsetup luksFormat for
us.
zkey seems to have no native support for invoking cryptsetup luksAddKey,
so we need to manually call it if we want to add a recovery key in a
second slot.
Turn off migration to deb822 by default, and update appropriate
docs/test to reflect this. When we are actually ready for this, the
logic in want_deb822() can be restored.
In LP: #2035034, a user reported that the layout of existing
partitions was showing as 1/8th the correct size. Update storage_config
to no longer hard-code a 512 byte sector and read the value instead.
If you try hard enough and follow mount commands backwards you can
surely get this same information, but when analyzing what the extract is
actually doing it's nice to just be able to see what the image stack is.
distro: remove disabling of deb-src lines in apt_update
The current code has the side-effect of ignoring deb822 .sources files
which is a problem that could be fixed but really it's hard to see why
this code is still useful (we do not expect to deploy images with
deb-src enabled!) so just deleting it makes more sense.