[go][dep] Init new codebase

[at15]

Like Xephon-B, it should make use of go.ice and libstdb-go, might need to adjust go.ice and gommon along the way ...

• old codebase will be kept, we will start a new package called xk which is just another name of pkg, it's better than pkgv2 ...
  • simply ask dep to ignore the pkg package would work I suppose
• empty cmd for server
• grpc server
• http server
• simple in memory storage