metropolis/node: move misplaced packages out of core

abloader, bios_bootcode and minit don't run as part of the core process,
so it doesn't make sense to have them in //metropolis/node/core.
This changes moves these three to //metropolis/node.

Change-Id: I908efb311a138f07a9f1de8e3c23437ff00131ee
Reviewed-on: https://review.monogon.dev/c/monogon/+/4196
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/core/update/update.go b/metropolis/node/core/update/update.go
index 6e41768..3d3060d 100644
--- a/metropolis/node/core/update/update.go
+++ b/metropolis/node/core/update/update.go
@@ -36,7 +36,7 @@
 	"source.monogon.dev/osbase/oci/registry"
 	"source.monogon.dev/version"
 
-	abloaderpb "source.monogon.dev/metropolis/node/core/abloader/spec"
+	abloaderpb "source.monogon.dev/metropolis/node/abloader/spec"
 	apb "source.monogon.dev/metropolis/proto/api"
 )
 
@@ -425,7 +425,7 @@
 	return nil
 }
 
-//go:embed metropolis/node/core/abloader/abloader_bin.efi
+//go:embed metropolis/node/abloader/abloader_bin.efi
 var abloader []byte
 
 func (s *Service) fixupPreloader() error {