Remove JetBrains.Annotations dependency

[Pliner]

No description provided.

[luigiberrettini]

I think it would be better to remove the attributes we do not use from Source/EasyNetQ.Management.Client/JetBrains/Annotations.cs

[zidad]

@Pliner @luigiberrettini I think we should be able to include it as a nuget package, but mark all its assets as private: NuGet/Home#4125

[luigiberrettini]

Thanks @zidad, but isn't that useful for development dependencies only?

[zidad]

Yeah but I thought it was, from the nuget package: "All usages of ReSharper Annotations attributes are erased from metadata by default, which means no actual binary reference to 'JetBrains.Annotations.dll' assembly is produced. If you need to preserve these attributes in metadata, just define 'JETBRAINS_ANNOTATIONS' conditional compilation symbol in your projects."