m/node: add Management service, implement GetRegisterTicket RPC

This follows the Cluster Lifecycle design document.

DO NOT MERGE: this needs a stacked CL on top which implements
authentication for the Management service.

Change-Id: I19422a63b9dbf2fc0c7f4cbe204851af35b4dbdf
Reviewed-on: https://review.monogon.dev/c/monogon/+/307
Reviewed-by: Mateusz Zalega <mateusz@monogon.tech>
diff --git a/metropolis/proto/api/BUILD.bazel b/metropolis/proto/api/BUILD.bazel
index 5004440..61d14fb 100644
--- a/metropolis/proto/api/BUILD.bazel
+++ b/metropolis/proto/api/BUILD.bazel
@@ -8,6 +8,7 @@
         "aaa.proto",
         "configuration.proto",
         "debug.proto",
+        "management.proto",
     ],
     visibility = ["//visibility:public"],
 )