reactor rpc (#179)

* reactor rpc generation

* update flag

* update command

* update command

* update unit test

* delete test file

* optimize code

* update doc

* update gen pb

* rename target dir

* update mysql data type convert rule

* add done flag

* optimize req/reply parameter

* optimize req/reply parameter

* remove waste code

* remove duplicate parameter

* format code

* format code

* optimize naming

* reactor rpcv2 to rpc

* remove new line

* format code

* rename underline to snake

* reactor getParentPackage

* remove debug log

* reactor background

tools/goctl/rpc/parser/test_option.proto

@@ -0,0 +1,10 @@
+syntax = "proto3";
+
+package stream;
+
+option go_package="github.com/tal-tech/go-zero";
+
+message placeholder{}
+service greet{
+  rpc hello(placeholder)returns(placeholder);
+}