Add JMH benchmarks for FIXMessageEncoder and FIXMessageDecoder

[Copilot]

Adds FIXMessageCodecPerfTest to the quickfixj-perf-test module to measure encoding/decoding throughput and latency for FIX 4.4 NewOrderSingle, with and without a repeating group.

Benchmarks

• encodeWithoutGroup / encodeWithGroup — calls FIXMessageEncoder.encode() with a plain NewOrderSingle and one with two NoAllocs (tag 78) entries
• decodeWithoutGroup / decodeWithGroup — calls FIXMessageDecoder.decode() on a pre-filled IoBuffer; buffer.rewind() resets the read position each iteration (decoder resets to SEEKING_HEADER internally after each successful parse)

Message construction

// Plain order
NewOrderSingle order = new NewOrderSingle(
        new ClOrdID("ORDER-001"), new Side(Side.BUY),
        new TransactTime(LocalDateTime.of(2006, 3, 24, 1, 5, 58)),
        new OrdType(OrdType.LIMIT));
order.set(new Symbol("AAPL"));
order.set(new OrderQty(100));
order.set(new Price(150.00));

// With NoAllocs repeating group (tag 78)
NewOrderSingle.NoAllocs alloc = new NewOrderSingle.NoAllocs();
alloc.set(new AllocAccount("ACC1"));
alloc.set(new AllocQty(50));
order.addGroup(alloc);

Inherits standard JMH settings from AbstractPerfTest: 3 warmup / 5 measurement iterations, 1 fork, Throughput + SampleTime output in nanoseconds.