Workflow format

We should make sure that something like [napari/dask-based-workflows](https://github.com/haesleinhuepf/napari-workflows/blob/main/docs/demo.ipynb) are compatible to this format:
https://github.com/clij/pycle_distributed_dask_prototype/blob/12c1925f31c0ce116d1b0aa5640a0e05c84eee83/tests/slurm_cluster_tests.py#L14

A napari-workflow looks pretty much like this under the hood:
```
{
"input": (imread, filename)
"blurred": (gaussian, sigma=5)
}
```