cloud/bmaas/bmdb/scruffy: initialize, implement BMDB metrics

This creates a new BMaaS component, Scruffy the Janitor.

Scruffy will run a bunch of housekeeping jobs that aren't tied to a
particular provider or even region. Currently Scruffy just collects BMDB
metrics by periodically polling the BMDB SQL database.

Change-Id: Icafa714811757eaaf31fed43184ded8512bde067
Reviewed-on: https://review.monogon.dev/c/monogon/+/1819
Tested-by: Jenkins CI
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
diff --git a/cloud/bmaas/bmdb/model/BUILD.bazel b/cloud/bmaas/bmdb/model/BUILD.bazel
index aea0d7b..bb00a08 100644
--- a/cloud/bmaas/bmdb/model/BUILD.bazel
+++ b/cloud/bmaas/bmdb/model/BUILD.bazel
@@ -8,6 +8,7 @@
     migrations = glob(["migrations/*sql"]),
     queries = [
         "queries_base.sql",
+        "queries_stats.sql",
         "queries_tags.sql",
         "queries_workflows.sql",
     ],
@@ -15,7 +16,10 @@
 
 go_library(
     name = "model",
-    srcs = ["migrations.go"],
+    srcs = [
+        "interfaces.go",
+        "migrations.go",
+    ],
     embed = [
         ":sqlc_model",  # keep
     ],