change grpc_tools_node_protoc_plugin binary name to protoc-gen-js-grpc

### Is your feature request related to a problem? Please describe.
Compatibility issues with already existing `protoc`, I needed to make a symbolic link from `grpc_tools_node_protoc_plugin` to `protoc-gen-js-grpc` so I can execute succesfully the command:
```sh
$ protoc --js-grpc_out=directory/
```
The java, c#, ruby, python and golang plugins has this behaviour, all of the plugins called `protoc-gen--grpc` and being succesfully invoked from protoc and generating its respective classes and methods.