Add a http snoop server sample

[longkunbetter]

Add a 'http snoop server' sample which receives any request and tells the client the details of the request in a formatted string #{761}

This is a sample http server that corresponds to HttpSnoopServer in examples of project netty.

Please notice that the http snoop server is not the same as the http echo server.
It will return the details of the request, not only the request body.
So I think it is a good example for people who want to learn how to use reactor-netty to build a http server and have a full control of the request and response.

I have tested it and it works well.

I'm unfamilar with such PR operation, if there is any problem please tell me.

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[longkunbetter]

#761

[violetagg]

@longkunbetter Thanks for the PR.

Can you use the same pattern as below link (for system properties etc.)

https://github.com/reactor/reactor-netty/tree/main/reactor-netty-examples/src/main/java/reactor/netty/examples/http/helloworld

[longkunbetter]

@violetagg Thanks for your feedback.
I'll adjust my code soon.

[longkunbetter]

@violetagg
I have adjusted the code style to be consistent with the rest of the project.
In the original version, I want to let my code be a bit more object-oriented, but it seems that it is too tedious to do so for a simple code.

[violetagg]

@longkunbetter Can you fix the import

/home/runner/work/reactor-netty/reactor-netty/reactor-netty-examples/src/main/java/reactor/netty/examples/http/snoop/HttpSnoopClient.java:64: error: cannot find symbol

				      .send(ByteBufMono.fromString(Mono.just("{\"foo\": 1,\"bar\": 2}")))

[longkunbetter]

@longkunbetter Can you fix the import

/home/runner/work/reactor-netty/reactor-netty/reactor-netty-examples/src/main/java/reactor/netty/examples/http/snoop/HttpSnoopClient.java:64: error: cannot find symbol

				      .send(ByteBufMono.fromString(Mono.just("{\"foo\": 1,\"bar\": 2}")))

I have fixed it. Should I squash my commits?

[violetagg]

Should I squash my commits?

No need I can squash them

[violetagg]

The tests failure on CI with Mac OS is not relevant to this PR

[violetagg]

@longkunbetter Thanks again for the PR!

[longkunbetter]

@longkunbetter Thanks again for the PR!

No thanks, I'm glad to contribute to this project.
Perhaps I will contribute more in the future, before that I need to learn more about the code style of this project.