Move napari workflows wrapper task into its own repository

[jluethi]

Goal:

1. Move napari workflows wrapper task into its own repository (to avoid dependency complications in tasks-core)
2. Replace it with a basic scikit-image measurement task in the core repo (so that we can show an easy example for measurements)

[jluethi]

I initially wanted to drop the requirement for adding basic measurements when we remove napari workflows. Unfortunately, that will make it hard to have self-contained examples like the current examples 01 & 02 that work with a single task package.

Thus, I think we should add this basic measurement task based on ngio before we make a fractal-tasks-core release without napari workflows.

And once we have that release, we'll need to update the Zenodo datasets with new measurements and adapt the example we run in regular tests.