feat: Support for multiple rpc service generation and rpc grouping (#1972)

* Add group & compatible flag

* Add group & compatible flag

* Support for multiple rpc service generation and rpc grouping

* Support for multiple rpc service generation and rpc grouping

* Format code

* Format code

* Add comments

* Fix unit test

* Refactor function name

* Add example & Update grpc readme

* go mod tidy

* update mod

* update mod

tools/goctl/example/rpc/hello/internal/server/greet/greetserver.go

@@ -0,0 +1,28 @@
+// Code generated by goctl. DO NOT EDIT!
+// Source: hello.proto
+
+package server
+
+import (
+	"context"
+
+	"github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/internal/logic/greet"
+	"github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/internal/svc"
+	"github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/pb/hello"
+)
+
+type GreetServer struct {
+	svcCtx *svc.ServiceContext
+	hello.UnimplementedGreetServer
+}
+
+func NewGreetServer(svcCtx *svc.ServiceContext) *GreetServer {
+	return &GreetServer{
+		svcCtx: svcCtx,
+	}
+}
+
+func (s *GreetServer) SayHello(ctx context.Context, in *hello.HelloReq) (*hello.HelloResp, error) {
+	l := greetlogic.NewSayHelloLogic(ctx, s.svcCtx)
+	return l.SayHello(in)
+}