Expose aten poll interval in rabbitmq.conf

as `raft.adaptive_failure_detector.poll_interval`.

On systems under peak load, inter-node communication link congestion
can result in false positives and trigger QQ leader re-elections that
are unnecessary and could make the situation worse.

Using a higher poll interval would at least reduce the probability of
false positives.

Per discussion with @kjnilsson @mkuratczyk.

deps/rabbit/priv/schema/rabbit.schema

@@ -2312,6 +2312,20 @@ end}.
     end
 }.
 
+{mapping, "raft.adaptive_failure_detector.poll_interval", "aten.poll_interval", [
+{datatype, integer},
+{validators, ["non_zero_positive_integer"]}
+]}.
+
+{translation, "aten.poll_interval",
+  fun(Conf) ->
+      case cuttlefish:conf_get("raft.adaptive_failure_detector.poll_interval", Conf, undefined) of
+          undefined -> cuttlefish:unset();
+          Val       -> Val
+      end
+  end
+}.
+
 %%
 %% Backing queue version
 %%

deps/rabbit/test/config_schema_SUITE_data/rabbit.snippets

@@ -844,6 +844,13 @@ credential_validator.regexp = ^abc\\d+",
      ]}],
    []},
 
+   {raft_adaptive_failure_detector_poll_interval,
+   "raft.adaptive_failure_detector.poll_interval = 10000",
+   [{aten, [
+      {poll_interval, 10000}
+     ]}],
+   []},
+
   %%
   %% Backing queue version
   %%