Add NonreflectableMessage and support Protobuf v5

[wasphin]

See https://github.com/apache/brpc/pull/2722#issuecomment-2272559689 inspired by unreflectable_message of @oathdruid.

What problem does this PR solve?

Issue Number: #2757

Problem Summary:

隔离 Protobuf Message API，简化内部消息类型实现，简化后续 Protobuf 适配工作，支持 Protobuf 到 v5.28.0

What is changed and the side effects?

Changed:

Side effects:

• Performance effects(性能影响):

• Breaking backward compatibility(向后兼容性):

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Check List:

• Please make sure your changes are compilable(请确保你的更改可以通过编译).
• When providing us with a new feature, it is best to add related tests(如果你向我们增加一个新的功能, 请添加相关测试).
• Please follow Contributor Covenant Code of Conduct.(请遵循贡献者准则).