Use sets v2 for better performance

This doubles the publish rate using the repro steps from
#5312
and somewhat reduces the memory usage.

```
rabbitmqctl -n rabbit-0 set_policy --apply-to queues ha "cmq.*" '{"ha-mode":"exactly", "ha-params": 3, "ha-sync-mode": "automatic"}'

$ perf-test -ad false -f persistent -qa x-dead-letter-exchange=,x-dead-letter-routing-key=cmq-dlq,x-queue-master-locator=client-local,x-queue-version=1 -x 4 -y 0 -s 1000 -C 250000 -u cmq-input-v1
BEFORE: id: test-164723-973, sending rate avg: 6156 msg/s
AFTER: id: test-165708-401, sending rate avg: 11572 msg/s

$ perf-test -ad false -f persistent -qa x-dead-letter-exchange=,x-dead-letter-routing-key=cmq-dlq,x-queue-master-locator=client-local,x-queue-version=1,x-queue-mode=lazy -x 4 -y 0 -s 1000 -C 250000 -u cmq-input-v1lazy
BEFORE: id: test-165020-228, sending rate avg: 6239 msg/s
AFTER: id: test-165848-489, sending rate avg: 11758 msg/s

$ perf-test -ad false -f persistent -qa x-dead-letter-exchange=,x-dead-letter-routing-key=cmq-dlq,x-queue-master-locator=client-local,x-queue-version=2 -x 4 -y 0 -s 1000 -C 250000 -u cmq-input-v2
BEFORE: id: test-165314-597, sending rate avg: 6818 msg/s
AFTER: id: test-170027-308, sending rate avg: 13891 msg/s
```

deps/rabbit/src/rabbit_dead_letter.erl

@@ -104,7 +104,7 @@ group_by_queue_and_reason(Tables) ->
                            ensure_xdeath_event_count(Augmented, N),
                            Key, SeenKeys, Acc),
                   {sets:add_element(Key, SeenKeys), Acc1}
-          end, {sets:new(), []}, Tables),
+          end, {sets:new([{version, 2}]), []}, Tables),
     Grouped.
 
 update_x_death_header(Info, undefined) ->

deps/rabbit/src/rabbit_mirror_queue_master.erl

@@ -122,7 +122,7 @@ init_with_existing_bq(Q0, BQ, BQS) when ?is_amqqueue(Q0) ->
                backing_queue_state = BQS,
                seen_status         = #{},
                confirmed           = [],
-               known_senders       = sets:new(),
+               known_senders       = sets:new([{version, 2}]),
                wait_timeout        = rabbit_misc:get_env(rabbit, slave_wait_timeout, 15000)};
     {error, Reason} ->
         %% The GM can shutdown before the coordinator has started up

deps/rabbit/src/rabbit_mirror_queue_slave.erl

@@ -878,7 +878,7 @@ maybe_enqueue_message(
 
 get_sender_queue(ChPid, SQ) ->
     case maps:find(ChPid, SQ) of
-        error     -> {queue:new(), sets:new(), running};
+        error     -> {queue:new(), sets:new([{version, 2}]), running};
         {ok, Val} -> Val
     end.