metropolis: move curator client watches to curator/watcher

This replaces all the ad-hoc code to watch Curator node(s) with calls
through the new curator/watcher library.

Change-Id: Ie2a82b330e4108b9b725515cb10595916c38b323
Reviewed-on: https://review.monogon.dev/c/monogon/+/2263
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/node/core/metrics/BUILD.bazel b/metropolis/node/core/metrics/BUILD.bazel
index 88cdc1b..6483377 100644
--- a/metropolis/node/core/metrics/BUILD.bazel
+++ b/metropolis/node/core/metrics/BUILD.bazel
@@ -10,8 +10,10 @@
     importpath = "source.monogon.dev/metropolis/node/core/metrics",
     visibility = ["//visibility:public"],
     deps = [
+        "//go/types/mapsets",
         "//metropolis/node",
         "//metropolis/node/core/curator/proto/api",
+        "//metropolis/node/core/curator/watcher",
         "//metropolis/node/core/identity",
         "//metropolis/pkg/supervisor",
     ],