Create protobuf protoc Grain generator

[rogeralsing]

In Go, we have this Protoc.exe generator:
https://github.com/AsynkronIT/protoactor-go/blob/dev/protobuf/protoc-gen-typedgam/template.go

We need to have a similar for C#.
It should be possible to re-use the same Go generator and just switch out the template, no need to rebuild the actual generator in C#.

[raskolnikoov]

404 on the link

[cpx86]

https://github.com/AsynkronIT/protoactor-go/blob/dev/protobuf/protoc-gen-protoactor/template.go

[yindongfei]

404 again

[rogeralsing]

https://github.com/AsynkronIT/protoactor-go/blob/dev/protobuf/protoc-gen-csgrain/template.go

I'm working on translate the content to C# here. any day now