Add prometheus metrics to alloy

modules/services/postgresql.tf

@@ -16,3 +16,21 @@ resource "postgresql_database" "service_databases" {
   name     = each.key
   owner    = postgresql_role.service_roles[each.key].name
 }
+
+resource "random_password" "postgresql_metrics_collector_password" {
+  length  = 32
+  special = false
+}
+
+resource "postgresql_role" "metrics_collector_role" {
+  name     = "metrics_collector"
+  login    = true
+  password = random_password.postgresql_metrics_collector_password.result
+  search_path = ["postgres_exporter", "pg_catalog"]
+  roles = ["pg_monitor", "pg_read_all_stats"]
+}
+
+resource "postgresql_database" "metrics_collector_database" {
+  name     = "metrics_collector"
+  owner    = postgresql_role.metrics_collector_role.name
+}