Introduce pydantic model for channels

[tcompa]

No description provided.

[github-actions]

Coverage report

The coverage rate went from 82.67% to 82.94% ⬆️
The branch rate is 76%.

97.26% of new lines are covered.

Diff Coverage details (click to unfold)

fractal_tasks_core/tasks/create_ome_zarr.py

100% of new lines are covered (82.97% of the complete file).

fractal_tasks_core/tasks/yokogawa_to_ome_zarr.py

100% of new lines are covered (84.68% of the complete file).

fractal_tasks_core/tasks/napari_workflows_wrapper.py

100% of new lines are covered (88.35% of the complete file).

fractal_tasks_core/lib_channels.py

96.49% of new lines are covered (91.56% of the complete file).
Missing lines: 29, 294

fractal_tasks_core/tasks/create_ome_zarr_multiplex.py

100% of new lines are covered (86.97% of the complete file).

fractal_tasks_core/tasks/illumination_correction.py

100% of new lines are covered (77.2% of the complete file).

fractal_tasks_core/tasks/cellpose_segmentation.py

100% of new lines are covered (82% of the complete file).

[tcompa]

A first version of this PR is ready, but I'll need to review it a bit more carefully.
Also, I'll have to double check it as part of fractal-analytics-platform/fractal-demos#54.

If this all goes smoothly, then a bunch of related issues should be "easy" to address (#414, #412, #404, #401).