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/svc/servicecontext.go

@@ -0,0 +1,13 @@
+package svc
+
+import "github.com/zeromicro/go-zero/tools/goctl/example/rpc/hello/internal/config"
+
+type ServiceContext struct {
+	Config config.Config
+}
+
+func NewServiceContext(c config.Config) *ServiceContext {
+	return &ServiceContext{
+		Config: c,
+	}
+}