m/c/metroctl: implement the "describe" command

This implements metroctl's "describe".

cmd.TerminateIfFound was adjusted to meet new test needs.

Change-Id: If86f35bc648d99396e7d5be48ab459d6b13334ce
Reviewed-on: https://review.monogon.dev/c/monogon/+/850
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/cli/metroctl/BUILD.bazel b/metropolis/cli/metroctl/BUILD.bazel
index 38ed5ae..9b4d6ec 100644
--- a/metropolis/cli/metroctl/BUILD.bazel
+++ b/metropolis/cli/metroctl/BUILD.bazel
@@ -5,6 +5,7 @@
     srcs = [
         "approve.go",
         "credentials.go",
+        "describe.go",
         "format.go",
         "install.go",
         "k8scredplugin.go",
@@ -30,6 +31,7 @@
         "//metropolis/node/core/identity",
         "//metropolis/node/core/rpc",
         "//metropolis/proto/api",
+        "//metropolis/proto/common",
         "@com_github_adrg_xdg//:xdg",
         "@com_github_spf13_cobra//:cobra",
         "@io_k8s_apimachinery//pkg/apis/meta/v1:meta",