Add support for passing a PathLike to functions that accept filenames

### 📝 Description of the feature

I want to be able to use pathlib everywhere it makes sense
```py
# Create output directory for results
out = Path("out").mkdir(exist_ok=True)
...
graphics.picture.save_picture(file_name=out / "catalytic_converter_mesh.png")
```

### 💡 Steps for implementing the feature

Add to flobject.py, also needs changing in the generator to fix the type hints

### 🔗 Useful links and references

_No response_