`RegisterGRPCGatewayRoutes` placeholder in `module.go`

[fadeev]

As far as I can tell there is really no point in having this placeholder.

// x/MODULE_NAME/module.go:

func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux) {
  // this line is used by starport scaffolding # 2
}

Shall we remove it and scaffold the right thing from the beginning?

func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux) {
  types.RegisterQueryHandlerClient(context.Background(), mux, types.NewQueryClient(clientCtx))
}