Support for custom pytorch ops

## Is there a way to use torchscript model with custom ops?
I'm trying to run pytorch geometric model with DJL and have a problem with custom ops from pytorch scatter library. The error is

```
Exception in thread "main" ai.djl.engine.EngineException:
Unknown builtin op: torch_sparse::ptr2ind.
Could not find any similar ops to torch_sparse::ptr2ind. This op may not exist or may not be currently supported in TorchScript.
```

Will it be enough to just compile and install the required library or its a more complex case with JNI involved ?

Thanks in advance