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/logic/greet/sayhellologic.go

@@ -0,0 +1,30 @@
+package greetlogic
+
+import (
+	"context"
+
+	"github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/internal/svc"
+	"github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/pb/hello"
+
+	"github.com/zeromicro/go-zero/core/logx"
+)
+
+type SayHelloLogic struct {
+	ctx    context.Context
+	svcCtx *svc.ServiceContext
+	logx.Logger
+}
+
+func NewSayHelloLogic(ctx context.Context, svcCtx *svc.ServiceContext) *SayHelloLogic {
+	return &SayHelloLogic{
+		ctx:    ctx,
+		svcCtx: svcCtx,
+		Logger: logx.WithContext(ctx),
+	}
+}
+
+func (l *SayHelloLogic) SayHello(in *hello.HelloReq) (*hello.HelloResp, error) {
+	// todo: add your logic here and delete this line
+
+	return &hello.HelloResp{}, nil
+}