c/agent: add initramfs build

The agent will be used directly on top of a Monogon kernel as an
initamfs. Add build rules for generating said initramfs.

Change-Id: I960fb3d82d4a7f227db48ca0714c48c63958d31f
Reviewed-on: https://review.monogon.dev/c/monogon/+/1142
Tested-by: Leopold Schabel <leo@monogon.tech>
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/cloud/agent/main.go b/cloud/agent/main.go
index 210739a..704b252 100644
--- a/cloud/agent/main.go
+++ b/cloud/agent/main.go
@@ -7,6 +7,7 @@
 )
 
 func main() {
+	fmt.Println("Monogon BMaaS Agent started")
 	report, errs := gatherHWReport()
 	// Just print the report for now
 	fmt.Println(prototext.Format(report))