Implemented a formatter for MessagePack for performance reasons

[zbalkan]

I needed a binary formatted message for performance reasons. So, I used MessagePack to achieve this goal. Also, it is possible with MessagePack to convert to JSON for debugging purposes. In my project, I used a couple of #IF DEBUGs but it would be unnecessary for this context. The performance gain is not huge but it helps when the traffic load gets higher.

Currently, it only supports .NET Standard 2.0 and above. .NET Framework support does not exist.

P.S: Initially I was planning to use ZeroFormatter, but since the benchmarks show no significant gain and MessagePack has the ability to convert to JSON quickly, I took that path.

P.S 2: You created such a nicely crafted library that implementing such a thing was trivial. I appreciate your craftsmanship! Since I used this in my personal project, I believe it would be better to contribute to the project itself.

[HavenDV]

I'll explain a little - now that you use MessagePackAnalyzer, this library and its dependencies will be delivered along with your other libraries. Therefore, you need to use PrivateAssets="all" so that the library is available only at compile time
I added a PR with DevelopmentDependency for the MessagePackAnalyzer to do this automatically after install package: MessagePack-CSharp/MessagePack-CSharp#1361

[HavenDV]

I have corrected the location of the projects and the .csproj themselves a bit. Note that although not explicitly supported by the .Net Framework, .Net Standard 2.0 is available from .Net Framework 4.6.1/4.7.2.