m/c/metroctl: implement the approve command

This adds a command to approve new nodes, and list nodes pending
approval.

Change-Id: I8f91d6e549c1eae298c5a4a6f11b53ae70a77f79
Reviewed-on: https://review.monogon.dev/c/monogon/+/825
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/cli/metroctl/BUILD.bazel b/metropolis/cli/metroctl/BUILD.bazel
index e8dc410..4ecdd60 100644
--- a/metropolis/cli/metroctl/BUILD.bazel
+++ b/metropolis/cli/metroctl/BUILD.bazel
@@ -3,6 +3,7 @@
 go_library(
     name = "metroctl_lib",
     srcs = [
+        "approve.go",
         "credentials.go",
         "install.go",
         "k8scredplugin.go",
@@ -23,6 +24,7 @@
         "//metropolis/cli/pkg/context",
         "//metropolis/cli/pkg/datafile",
         "//metropolis/node",
+        "//metropolis/node/core/identity",
         "//metropolis/node/core/rpc",
         "//metropolis/node/core/rpc/resolver",
         "//metropolis/proto/api",