commands/search: Introduce the --cryptodisk-only argument

commands/search: Introduce the --cryptodisk-only argument

This allows users to restrict the "search" command's scope to
encrypted disks only.

Typically, this command is used to "rebase" $root and $prefix
before loading additional configuration files via "source" or
"configfile". Unfortunately, this leads to security problems,
like CVE-2023-4001, when an unexpected, attacker-controlled
device is chosen by the "search" command.

The --cryptodisk-only argument allows users to ensure that the
file system picked is encrypted.

This feature supports the CLI authentication, blocking bypass
attempts.

Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>