Suggesting support SPEL for @RocketMQMessageListener topic resolution

[qingzhou413]

1. Please describe the feature you are requesting.

When using @RocketMQMessageListener like below:

@RocketMQMessageListener(
        nameServer = "${rocketmq.name-server}",
        topic = "'TP_' + T(java.net.InetAddress).getLocalHost().getHostAddress().replace('.', '_')",
        consumerGroup = "${rocketmq.consumer.group}",
        accessKey = "${rocketmq.consumer.access-key}",
        secretKey = "${rocketmq.consumer.secret-key}"
)

Sometimes we want to set topic at runtime, but currently only support placeholders.

[RongtongJin]

In general, the topic should be fixed, not determined at runtime. IMO, this is not a necessary feature.