This adds `settings.boot` to help configure kernel boot config settings.

 - Adds new subcommand `generate-boot-config` to generate an initrd
image file with boot config contents populated from Bottlerocket boot
settings.
 - Adds new subcommand `generate-boot-settings` to generate bottlerocket
settings from kernel's bootconfig file at `/proc/bootconfig`

Moves prairiedog from `sources/prairiedog` to `sources/api/prairiedog`
now that it needs to query from the Bottlerocket API and need settings
model information.

This updates the settings retrieval to use prefixes for matching and
querying. We cannot use full keys for matching because we now have
settings generator for keys that map to top level structs that
encompasses multiple settings.

Add settings generator for `settings.boot` and restart commands for when
boot settings change.

We've added bootconfig support so console settings should be specified
through there. The console settings specified to the kernel commandline
will always take effect, so we're removing them from the variant
metadata.