manifest: add grub config for OSTreeDeployment

These are based on the official Fedora IoT Raw Image but are added to
the base OSTreeDeployment manifest.  For now, let's add them to all
ostree deployments that will use these new types and we can extract the
values to make them configurable when we need to.

internal/manifest/commit_deployment.go

@@ -2,6 +2,7 @@ package manifest
 
 import (
 	"os"
+	"strings"
 
 	"github.com/osbuild/osbuild-composer/internal/common"
 	"github.com/osbuild/osbuild-composer/internal/disk"
@@ -188,13 +189,20 @@ func (p *OSTreeDeployment) serialize() osbuild.Pipeline {
 	// TODO: Add users?
 	// NOTE: Users can be embedded in a commit, but we should also support adding them at deploy time.
 
-	options := osbuild.NewGrub2StageOptionsUnified(p.PartitionTable,
+	grubOptions := osbuild.NewGrub2StageOptionsUnified(p.PartitionTable,
 		"",
 		p.platform.GetUEFIVendor() != "",
 		p.platform.GetBIOSPlatform(),
 		p.platform.GetUEFIVendor(), true)
-	options.Greenboot = true
-	bootloader := osbuild.NewGRUB2Stage(options)
+	grubOptions.Greenboot = true
+	grubOptions.Config = &osbuild.GRUB2Config{
+		Default:        "saved",
+		Timeout:        1,
+		TerminalOutput: []string{"console"},
+	}
+	grubOptions.KernelOptions = strings.Join(kernelOpts, ",")
+	bootloader := osbuild.NewGRUB2Stage(grubOptions)
+	bootloader.MountOSTree(p.osName, p.osTreeRef, 0)
 	pipeline.AddStage(bootloader)
 
 	pipeline.AddStage(osbuild.NewOSTreeSelinuxStage(