use customized rpc implementation, remove Tarpc & Tonic (#348)

This patch removes Tarpc & Tonic GRPC and implements a customized rpc framework, which can be used by peer rpc and cli interface.

web config server can also use this rpc framework.

moreover, rewrite the public server logic, use ospf route to implement public server based networking. this make public server mesh possible.

easytier/src/proto/tests.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package tests;
+
+/// The Greeting service. This service is used to generate greetings for various
+/// use-cases.
+service Greeting {
+  // Generates a "hello" greeting based on the supplied info.
+  rpc SayHello(SayHelloRequest) returns (SayHelloResponse);
+  // Generates a "goodbye" greeting based on the supplied info.
+  rpc SayGoodbye(SayGoodbyeRequest) returns (SayGoodbyeResponse);
+}
+
+// The request for an `Greeting.SayHello` call.
+message SayHelloRequest { string name = 1; }
+
+// The response for an `Greeting.SayHello` call.
+message SayHelloResponse { string greeting = 1; }
+
+// The request for an `Greeting.SayGoodbye` call.
+message SayGoodbyeRequest { string name = 1; }
+
+// The response for an `Greeting.SayGoodbye` call.
+message SayGoodbyeResponse { string greeting = 1; }